FileUpload Class

Reference

Definition

Namespace:: System.Web.UI.WebControls

Assembly:: System.Web.dll

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Displays a text box control and a browse button that enable users to select a file to upload to the server.

public ref class FileUpload : System::Web::UI::WebControls::WebControl

[System.Web.UI.ControlValueProperty("FileBytes")]
[System.Web.UI.ValidationProperty("FileName")]
public class FileUpload : System.Web.UI.WebControls.WebControl

[<System.Web.UI.ControlValueProperty("FileBytes")>]
[<System.Web.UI.ValidationProperty("FileName")>]
type FileUpload = class
    inherit WebControl

Public Class FileUpload
Inherits WebControl

Inheritance: Object

Control

WebControl
FileUpload

Attributes: ControlValuePropertyAttribute ValidationPropertyAttribute

Examples

A Visual Studio Web site project with source code is available to accompany this topic: Download.

This section contains the following four examples:

The first example demonstrates how to create a FileUpload control that saves files to a path that is specified in code.
The second example demonstrates how to create a FileUpload control that saves files to a specified directory in the file system for the application.
The third example demonstrates how to create a FileUpload control that saves files to a specified path and limits the size of the file that can be uploaded.
The fourth example demonstrates how to create a FileUpload control that saves files to a specified path and allows only files that have the .doc or .xls file name extensions to be uploaded.

Caution

These examples demonstrate the basic syntax for the FileUpload control, but they do not demonstrate all the necessary error checking that should be completed before to saving the file. For a more complete example, see SaveAs.

The following example demonstrates how to create a FileUpload control that saves files to a path that is specified in code. The SaveAs method is called to save the file to the specified path on the server.

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 

<script runat="server">

  protected void UploadButton_Click(object sender, EventArgs e)
  {
    // Specify the path on the server to
    // save the uploaded file to.
    String savePath = @"c:\temp\uploads\";
 
    // Before attempting to perform operations
    // on the file, verify that the FileUpload 
    // control contains a file.
    if (FileUpload1.HasFile)
    {
      // Get the name of the file to upload.
      String fileName = FileUpload1.FileName;
      
      // Append the name of the file to upload to the path.
      savePath += fileName;
      

      // Call the SaveAs method to save the 
      // uploaded file to the specified path.
      // This example does not perform all
      // the necessary error checking.               
      // If a file with the same name
      // already exists in the specified path,  
      // the uploaded file overwrites it.
      FileUpload1.SaveAs(savePath);
      
      // Notify the user of the name of the file
      // was saved under.
      UploadStatusLabel.Text = "Your file was saved as " + fileName;
    }
    else
    {      
      // Notify the user that a file was not uploaded.
      UploadStatusLabel.Text = "You did not specify a file to upload.";
    }

  }
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>FileUpload Example</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
       <h4>Select a file to upload:</h4>
   
       <asp:FileUpload id="FileUpload1"                 
           runat="server">
       </asp:FileUpload>
            
       <br /><br />
       
       <asp:Button id="UploadButton" 
           Text="Upload file"
           OnClick="UploadButton_Click"
           runat="server">
       </asp:Button>    
       
       <hr />
       
       <asp:Label id="UploadStatusLabel"
           runat="server">
       </asp:Label>        
    </div>
    </form>
</body>
</html>

<%@ Page Language="VB" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 

<script runat="server">
        
  Sub UploadButton_Click(ByVal sender As Object, ByVal e As System.EventArgs)
            
    ' Specify the path on the server to
    ' save the uploaded file to.
    Dim savePath As String = "c:\temp\uploads\"
            
    ' Before attempting to perform operations
    ' on the file, verify that the FileUpload 
    ' control contains a file.
    If (FileUpload1.HasFile) Then
      ' Get the name of the file to upload.
      Dim fileName As String = FileUpload1.FileName
                      
      ' Append the name of the file to upload to the path.
      savePath += fileName
                
      ' Call the SaveAs method to save the 
      ' uploaded file to the specified path.
      ' This example does not perform all
      ' the necessary error checking.               
      ' If a file with the same name
      ' already exists in the specified path,  
      ' the uploaded file overwrites it.
      FileUpload1.SaveAs(savePath)
                
      ' Notify the user of the name the file
      ' was saved under.
      UploadStatusLabel.Text = "Your file was saved as " & fileName
                
    Else
      ' Notify the user that a file was not uploaded.
      UploadStatusLabel.Text = "You did not specify a file to upload."
    End If

  End Sub
       
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>FileUpload Example</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
       <h4>Select a file to upload:</h4>
   
       <asp:FileUpload id="FileUpload1"                 
           runat="server">
       </asp:FileUpload>
            
       <br /><br />
       
       <asp:Button id="UploadButton" 
           Text="Upload file"
           OnClick="UploadButton_Click"
           runat="server">
       </asp:Button>    
       
       <hr />
       
       <asp:Label id="UploadStatusLabel"
           runat="server">
       </asp:Label>        
    </div>
    </form>
</body>
</html>

The following example demonstrates how to create a FileUpload control that saves files to a specified directory in the file system for the application. The HttpRequest.PhysicalApplicationPath property is used to get the physical file system path of the root directory for the currently executing server application. The SaveAs method is called to save the file to the specified path on the server.

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

    protected void UploadButton_Click(object sender, EventArgs e)
    {
        // Save the uploaded file to an "Uploads" directory
        // that already exists in the file system of the 
        // currently executing ASP.NET application.  
        // Creating an "Uploads" directory isolates uploaded 
        // files in a separate directory. This helps prevent
        // users from overwriting existing application files by
        // uploading files with names like "Web.config".
        string saveDir = @"\Uploads\";

        // Get the physical file system path for the currently
        // executing application.
        string appPath = Request.PhysicalApplicationPath;

        // Before attempting to save the file, verify
        // that the FileUpload control contains a file.
        if (FileUpload1.HasFile)
        {
            string savePath = appPath + saveDir +
                Server.HtmlEncode(FileUpload1.FileName);
            
            // Call the SaveAs method to save the 
            // uploaded file to the specified path.
            // This example does not perform all
            // the necessary error checking.               
            // If a file with the same name
            // already exists in the specified path,  
            // the uploaded file overwrites it.
            FileUpload1.SaveAs(savePath);

            // Notify the user that the file was uploaded successfully.
            UploadStatusLabel.Text = "Your file was uploaded successfully.";

        }
        else
        {
            // Notify the user that a file was not uploaded.
            UploadStatusLabel.Text = "You did not specify a file to upload.";   
        }
    }
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>FileUpload Class Example</title>
</head>
<body>
    <h3>FileUpload Class Example: Save To Application Directory</h3>
    <form id="form1" runat="server">
    <div>
       <h4>Select a file to upload:</h4>
   
       <asp:FileUpload id="FileUpload1"                 
           runat="server">
       </asp:FileUpload>
            
       <br/><br/>
       
       <asp:Button id="UploadButton" 
           Text="Upload file"
           OnClick="UploadButton_Click"
           runat="server">
       </asp:Button>    
       
       <hr />
       
       <asp:Label id="UploadStatusLabel"
           runat="server">
       </asp:Label>           
    </div>
    </form>
</body>
</html>

<%@ Page Language="VB" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">
    Sub UploadButton_Click(ByVal sender As Object, ByVal e As System.EventArgs)
            
        ' Save the uploaded file to an "Uploads" directory
        ' that already exists in the file system of the 
        ' currently executing ASP.NET application.  
        ' Creating an "Uploads" directory isolates uploaded 
        ' files in a separate directory. This helps prevent
        ' users from overwriting existing application files by
        ' uploading files with names like "Web.config".
        Dim saveDir As String = "\Uploads\"
           
        ' Get the physical file system path for the currently
        ' executing application.
        Dim appPath As String = Request.PhysicalApplicationPath
            
        ' Before attempting to save the file, verify
        ' that the FileUpload control contains a file.
        If (FileUpload1.HasFile) Then
            Dim savePath As String = appPath + saveDir + _
                Server.HtmlEncode(FileUpload1.FileName)
                        
            ' Call the SaveAs method to save the 
            ' uploaded file to the specified path.
            ' This example does not perform all
            ' the necessary error checking.               
            ' If a file with the same name
            ' already exists in the specified path,  
            ' the uploaded file overwrites it.
            FileUpload1.SaveAs(savePath)
                
            ' Notify the user that the file was uploaded successfully.
            UploadStatusLabel.Text = "Your file was uploaded successfully."

        Else
            ' Notify the user that a file was not uploaded.
            UploadStatusLabel.Text = "You did not specify a file to upload."
        End If

    End Sub
       
</script>
    
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>FileUpload Class Example</title>
</head>
<body>
   <h3>FileUpload Class Example: Save To Application Directory</h3>
   <form id="form1" runat="server">
   <div>   
       <h4>Select a file to upload:</h4>
   
       <asp:FileUpload id="FileUpload1"                 
           runat="server">
       </asp:FileUpload>
            
       <br/><br/>
       
       <asp:Button id="UploadButton" 
           Text="Upload file"
           OnClick="UploadButton_Click"
           runat="server">
       </asp:Button>    
       
       <hr />
       
       <asp:Label id="UploadStatusLabel"
           runat="server">
       </asp:Label>       
         
   </div>
   </form>
</body>
</html>

The following example demonstrates how to create a FileUpload control that saves files to a path that is specified in the code. The control limits the size of the file that can be uploaded to 2 MB. The PostedFile property is used to access the underlying ContentLength property and return the size of the file. If the size of the file to upload is less than 2 MB, the SaveAs method is called to save the file to the specified path on the server. In addition to checking for the maximum file size setting in your application code, you can set the maxRequestLength attribute of the httpRuntime element to a maximum allowable size in the configuration file for your application.

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

    protected void UploadButton_Click(object sender, EventArgs e)
    {
        // Specify the path on the server to
        // save the uploaded file to.
        string savePath = @"c:\temp\uploads\";
                       
        // Before attempting to save the file, verify
        // that the FileUpload control contains a file.
        if (FileUpload1.HasFile)
        {                
            // Get the size in bytes of the file to upload.
            int fileSize = FileUpload1.PostedFile.ContentLength;
          
            // Allow only files less than 2,100,000 bytes (approximately 2 MB) to be uploaded.
            if (fileSize < 2100000)
            {
                        
                // Append the name of the uploaded file to the path.
                savePath += Server.HtmlEncode(FileUpload1.FileName);

                // Call the SaveAs method to save the 
                // uploaded file to the specified path.
                // This example does not perform all
                // the necessary error checking.               
                // If a file with the same name
                // already exists in the specified path,  
                // the uploaded file overwrites it.
                FileUpload1.SaveAs(savePath);
                
                // Notify the user that the file was uploaded successfully.
                UploadStatusLabel.Text = "Your file was uploaded successfully.";
            }
            else
            {
                // Notify the user why their file was not uploaded.
                UploadStatusLabel.Text = "Your file was not uploaded because " + 
                                         "it exceeds the 2 MB size limit.";
            }
        }   
        else
        {
            // Notify the user that a file was not uploaded.
            UploadStatusLabel.Text = "You did not specify a file to upload.";
        }
    }
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>FileUpload Class Example</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
       <h4>Select a file to upload:</h4>
   
       <asp:FileUpload id="FileUpload1"                 
           runat="server">
       </asp:FileUpload>
            
       <br/><br/>
       
       <asp:Button id="UploadButton" 
           Text="Upload file"
           OnClick="UploadButton_Click"
           runat="server">
       </asp:Button>
       
       <hr />
       
       <asp:Label id="UploadStatusLabel"
           runat="server">
       </asp:Label>
           
    </div>
    </form>
</body>
</html>

<%@ Page Language="VB" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

    Protected Sub UploadButton_Click(ByVal sender As Object, ByVal e As System.EventArgs)
        
        ' Specify the path on the server to
        ' save the uploaded file to.
        Dim savePath As String = "c:\temp\uploads\"
                       
        ' Before attempting to save the file, verify
        ' that the FileUpload control contains a file.
        If (FileUpload1.HasFile) Then
                
            ' Get the size in bytes of the file to upload.
            Dim fileSize As Integer = FileUpload1.PostedFile.ContentLength
          
            ' Allow only files less than 2,100,000 bytes (approximately 2 MB) to be uploaded.
            If (fileSize < 2100000) Then
                        
                ' Append the name of the uploaded file to the path.
                savePath += Server.HtmlEncode(FileUpload1.FileName)

                ' Call the SaveAs method to save the 
                ' uploaded file to the specified path.
                ' This example does not perform all
                ' the necessary error checking.               
                ' If a file with the same name
                ' already exists in the specified path,  
                ' the uploaded file overwrites it.
                FileUpload1.SaveAs(savePath)
                
                ' Notify the user that the file was uploaded successfully.
                UploadStatusLabel.Text = "Your file was uploaded successfully."
            
            Else
                ' Notify the user why their file was not uploaded.
                UploadStatusLabel.Text = "Your file was not uploaded because " + _
                                         "it exceeds the 2 MB size limit."
            End If
                
        Else
            ' Notify the user that a file was not uploaded.
            UploadStatusLabel.Text = "You did not specify a file to upload."
        End If

    End Sub
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>FileUpload Class Example</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
       <h4>Select a file to upload:</h4>
   
       <asp:FileUpload id="FileUpload1"                 
           runat="server">
       </asp:FileUpload>
            
       <br/><br/>
       
       <asp:Button id="UploadButton" 
           Text="Upload file"
           OnClick="UploadButton_Click"
           runat="server">
       </asp:Button>
       
       <hr />
       
       <asp:Label id="UploadStatusLabel"
           runat="server">
       </asp:Label>
           
    </div>
    </form>
</body>
</html>

The following example demonstrates how to create a FileUpload control that saves files to a path that is specified in the code. This example allows only files that have the .doc or .xls file name extensions to be uploaded. The Path.GetExtension method is called to return the extension of the file to upload. If the file has a .doc or .xls file name extension, the SaveAs method is called to save the file to the specified path on the server.

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

    protected void UploadBtn_Click(object sender, EventArgs e)
    {
        // Specify the path on the server to
        // save the uploaded file to.
        string savePath = @"c:\temp\uploads";

        // Before attempting to save the file, verify
        // that the FileUpload control contains a file.
        if (FileUpload1.HasFile)
        {
            // Get the name of the file to upload.
            string fileName = Server.HtmlEncode(FileUpload1.FileName);

            // Get the extension of the uploaded file.
            string extension = System.IO.Path.GetExtension(fileName);
            
            // Allow only files with .doc or .xls extensions
            // to be uploaded.
            if ((extension == ".doc") || (extension == ".xls"))
            {
                // Append the name of the file to upload to the path.
                savePath += fileName;

                // Call the SaveAs method to save the 
                // uploaded file to the specified path.
                // This example does not perform all
                // the necessary error checking.               
                // If a file with the same name
                // already exists in the specified path,  
                // the uploaded file overwrites it.
                FileUpload1.SaveAs(savePath);
                
                // Notify the user that their file was successfully uploaded.
                UploadStatusLabel.Text = "Your file was uploaded successfully.";
            }
            else
            {
                // Notify the user why their file was not uploaded.
                UploadStatusLabel.Text = "Your file was not uploaded because " + 
                                         "it does not have a .doc or .xls extension.";
            }

        }

    }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>FileUpload Class Example</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <h4>Select a file to upload:</h4>
       
        <asp:FileUpload id="FileUpload1"                 
            runat="server">
        </asp:FileUpload>
            
        <br/><br/>
       
        <asp:Button id="UploadBtn" 
            Text="Upload file"
            OnClick="UploadBtn_Click"
            runat="server">
        </asp:Button>    
       
        <hr />
       
        <asp:Label id="UploadStatusLabel"
            runat="server">
        </asp:Label>     
    </div>
    </form>
</body>
</html>

<%@ Page Language="VB" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

    Protected Sub UploadBtn_Click(ByVal sender As Object, ByVal e As System.EventArgs)
        ' Specify the path on the server to
        ' save the uploaded file to.
        Dim savePath As String = "c:\temp\uploads\"
            
        ' Before attempting to save the file, verify
        ' that the FileUpload control contains a file.
        If (FileUpload1.HasFile) Then
            
            ' Get the name of the file to upload.
            Dim fileName As String = Server.HtmlEncode(FileUpload1.FileName)
            
            ' Get the extension of the uploaded file.
            Dim extension As String = System.IO.Path.GetExtension(fileName)
            
            ' Allow only files with .doc or .xls extensions
            ' to be uploaded.
            If (extension = ".doc") Or (extension = ".xls") Then
                        
                ' Append the name of the file to upload to the path.
                savePath += fileName
            
                ' Call the SaveAs method to save the 
                ' uploaded file to the specified path.
                ' This example does not perform all
                ' the necessary error checking.               
                ' If a file with the same name
                ' already exists in the specified path,  
                ' the uploaded file overwrites it.
                FileUpload1.SaveAs(savePath)
                
                ' Notify the user that their file was successfully uploaded.
                UploadStatusLabel.Text = "Your file was uploaded successfully."
            
            Else
                ' Notify the user why their file was not uploaded.
                UploadStatusLabel.Text = "Your file was not uploaded because " + _
                                         "it does not have a .doc or .xls extension."
            End If
                
        Else
            ' Notify the user that a file was not uploaded.
            UploadStatusLabel.Text = "You did not specify a file to upload."
        End If
    End Sub
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>FileUpload Class Example</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <h4>Select a file to upload:</h4>
       
        <asp:FileUpload id="FileUpload1"                 
            runat="server">
        </asp:FileUpload>
            
        <br/><br/>
       
        <asp:Button id="UploadBtn" 
            Text="Upload file"
            OnClick="UploadBtn_Click"
            runat="server">
        </asp:Button>    
       
        <hr />
       
        <asp:Label id="UploadStatusLabel"
            runat="server">
        </asp:Label>     
    </div>
    </form>
</body>
</html>

Remarks

In this topic:

Introduction
Saving Uploaded Files
Security Considerations
Memory Limitations
Using the FileUpload Control with the UpdatePanel Control
Declarative Syntax

Introduction

The FileUpload class displays a text box control and a browse button that enable users to select a file on the client and upload it to the Web server. The user specifies the file to upload by entering the full path of the file on the local computer (for example, C:\MyFiles\TestFile.txt) in the text box of the control. Alternately, the user can select the file by clicking the Browse button, and then locating it in the Choose File dialog box.

Use the FileName property to get the name of a file on a client to upload by using the FileUpload control. The file name that this property returns does not include the path of the file on the client.

The FileContent property gets a Stream object that points to a file to upload. Use this property to access the contents of the file as bytes. For example, you can use the Stream object that is returned by the FileContent property to read the contents of the file as bytes and store them in a byte array. Alternatively, you can use the FileBytes property to retrieve all the bytes in the file.

The PostedFile property gets the underlying HttpPostedFile object for the file to upload. You can use this property to access additional properties on the file. The ContentLength property gets the length of the file. The ContentType property gets the MIME content type of the file. In addition, you can use the PostedFile property to access the FileName property, the InputStream property, and the SaveAs method. However, the same functionality is provided by the FileName property, the FileContent property, and the SaveAs method.

Saving Uploaded Files

The FileUpload control does not automatically save a file to the server after the user selects the file to upload. You must explicitly provide a control or mechanism to allow the user to submit the specified file. For example, you can provide a button that the user clicks to upload the file. The code that you write to save the specified file should call the SaveAs method, which saves the contents of a file to a specified path on the server. Typically, the SaveAs method is called in an event-handling method for an event that raises a post back to the server. For example, if you provide a button to submit a file, you could include the code to save the file inside the event-handling method for the click event.

Before calling the SaveAs method to save the file to the server, use the HasFile property to verify that the FileUpload control contains a file. If the HasFile returns true, call the SaveAs method. If it returns false, display a message to the user indicating that the control does not contain a file. Do not check the PostedFile property to determine whether a file to upload exists because, by default, this property contains 0 bytes. As a result, even when the FileUpload control is blank, the PostedFile property returns a non-null value.

Security Considerations

When you call the SaveAs method, you must specify the full path of the directory in which to save the uploaded file. If you do not explicitly specify a path in your application code, an exception is thrown when a user attempts to upload a file. This behavior helps keep the files on the server secure by preventing users from being able to write to arbitrary locations in your application's directory structure, as well as preventing access to sensitive root directories.

The SaveAs method writes the uploaded file to the specified directory. Therefore, the ASP.NET application must have write access to the directory on the server. There are two ways that the application can get write access. You can explicitly grant write access to the account under which the application is running, in the directory in which the uploaded files will be saved. Alternatively, you can increase the level of trust that is granted to the ASP.NET application. To get write access to the executing directory for the application, the application must be granted the AspNetHostingPermission object with the trust level set to the AspNetHostingPermissionLevel.Medium value. Increasing the level of trust increases the application's access to resources on the server. Note that this is not a secure approach, because a malicious user who gains control of your application will also be able to run under this higher level of trust. It is a best practice to run an ASP.NET application in the context of a user with the minimum privileges that are required for the application to run. For more information about security in ASP.NET applications, see Basic Security Practices for Web Applications and ASP.NET Trust Levels and Policy Files.

Memory Limitations

One way to guard against denial of service attacks is to limit the size of the files that can be uploaded by using the FileUpload control. You should set a size limit that is appropriate for the types of files that you expect to be uploaded. The default size limit is 4096 kilobytes (KB), or 4 megabytes (MB). You can allow larger files to be uploaded by setting the maxRequestLength attribute of the httpRuntime element. To increase the maximum allowable file size for the entire application, set the maxRequestLength attribute in the Web.config file. To increase the maximum allowable file size for a specified page, set the maxRequestLength attribute inside the location element in Web.config. For an example, see location Element (ASP.NET Settings Schema).

When uploading large files, a user might also receive the following error message:

aspnet_wp.exe (PID: 1520) was recycled because memory consumption exceeded 460 MB (60 percent of available RAM).

If your users encounter this error message, increase the value of the memoryLimit attribute in the processModel of element the Web.config file for the application. The memoryLimit attribute specifies the maximum amount of memory that a worker process can use. If the worker process exceeds the memoryLimit amount, a new process is created to replace it, and all current requests are reassigned to the new process.

To control whether the file to upload is temporarily stored in memory or on the server while the request is being processed, set the requestLengthDiskThreshold attribute of the httpRuntime element. This attribute enables you to manage the size of the input stream buffer. The default is 256 bytes. The value that you specify should not exceed the value that you specify for the maxRequestLength attribute.

Using the FileUpload Control with the UpdatePanel Control

The FileUpload control is designed to be used only in postback scenarios and not in asynchronous postback scenarios during partial-page rendering. When you use a FileUpload control inside an UpdatePanel control, the file must be uploaded by using a control that is a PostBackTrigger object for the panel. UpdatePanel controls are used to update selected regions of a page instead of updating the whole page with a postback. For more information, see UpdatePanel Control Overview and Partial-Page Rendering Overview.

Declarative Syntax

<asp:FileUpload  
    AccessKey="string"  
    BackColor="color name|#dddddd"  
    BorderColor="color name|#dddddd"  
    BorderStyle="NotSet|None|Dotted|Dashed|Solid|Double|Groove|Ridge|  
        Inset|Outset"  
    BorderWidth="size"  
    CssClass="string"  
    Enabled="True|False"  
    EnableTheming="True|False"  
    EnableViewState="True|False"  
    Font-Bold="True|False"  
    Font-Italic="True|False"  
    Font-Names="string"  
    Font-Overline="True|False"  
    Font-Size="string|Smaller|Larger|XX-Small|X-Small|Small|Medium|  
        Large|X-Large|XX-Large"  
    Font-Strikeout="True|False"  
    Font-Underline="True|False"  
    ForeColor="color name|#dddddd"  
    Height="size"  
    ID="string"  
    OnDataBinding="DataBinding event handler"  
    OnDisposed="Disposed event handler"  
    OnInit="Init event handler"  
    OnLoad="Load event handler"  
    OnPreRender="PreRender event handler"  
    OnUnload="Unload event handler"  
    runat="server"  
    SkinID="string"  
    Style="string"  
    TabIndex="integer"  
    ToolTip="string"  
    Visible="True|False"  
    Width="size"  
/>

Constructors

FileUpload()

Initializes a new instance of the FileUpload class.

Properties

AccessKey	Gets or sets the access key that allows you to quickly navigate to the Web server control. (Inherited from WebControl)
Adapter	Gets the browser-specific adapter for the control. (Inherited from Control)
AllowMultiple	Gets or sets a value that specifies whether multiple files can be selected for upload.
AppRelativeTemplateSourceDirectory	Gets or sets the application-relative virtual directory of the Page or UserControl object that contains this control. (Inherited from Control)
Attributes	Gets the collection of arbitrary attributes (for rendering only) that do not correspond to properties on the control. (Inherited from WebControl)
BackColor	Gets or sets the background color of the Web server control. (Inherited from WebControl)
BindingContainer	Gets the control that contains this control's data binding. (Inherited from Control)
BorderColor	Gets or sets the border color of the Web control. (Inherited from WebControl)
BorderStyle	Gets or sets the border style of the Web server control. (Inherited from WebControl)
BorderWidth	Gets or sets the border width of the Web server control. (Inherited from WebControl)
ChildControlsCreated	Gets a value that indicates whether the server control's child controls have been created. (Inherited from Control)
ClientID	Gets the control ID for HTML markup that is generated by ASP.NET. (Inherited from Control)
ClientIDMode	Gets or sets the algorithm that is used to generate the value of the ClientID property. (Inherited from Control)
ClientIDSeparator	Gets a character value representing the separator character used in the ClientID property. (Inherited from Control)
Context	Gets the HttpContext object associated with the server control for the current Web request. (Inherited from Control)
Controls	Gets a ControlCollection object that represents the child controls for a specified server control in the UI hierarchy. (Inherited from Control)
ControlStyle	Gets the style of the Web server control. This property is used primarily by control developers. (Inherited from WebControl)
ControlStyleCreated	Gets a value indicating whether a Style object has been created for the ControlStyle property. This property is primarily used by control developers. (Inherited from WebControl)
CssClass	Gets or sets the Cascading Style Sheet (CSS) class rendered by the Web server control on the client. (Inherited from WebControl)
DataItemContainer	Gets a reference to the naming container if the naming container implements IDataItemContainer. (Inherited from Control)
DataKeysContainer	Gets a reference to the naming container if the naming container implements IDataKeysControl. (Inherited from Control)
DesignMode	Gets a value indicating whether a control is being used on a design surface. (Inherited from Control)
Enabled	Gets or sets a value indicating whether the Web server control is enabled. (Inherited from WebControl)
EnableTheming	Gets or sets a value indicating whether themes apply to this control. (Inherited from WebControl)
EnableViewState	Gets or sets a value indicating whether the server control persists its view state, and the view state of any child controls it contains, to the requesting client. (Inherited from Control)
Events	Gets a list of event handler delegates for the control. This property is read-only. (Inherited from Control)
FileBytes	Gets an array of the bytes in a file that is specified by using a FileUpload control.
FileContent	Gets a Stream object that points to a file to upload using the FileUpload control.
FileName	Gets the name of a file on a client to upload using the FileUpload control.
Font	Gets the font properties associated with the Web server control. (Inherited from WebControl)
ForeColor	Gets or sets the foreground color (typically the color of the text) of the Web server control. (Inherited from WebControl)
HasAttributes	Gets a value indicating whether the control has attributes set. (Inherited from WebControl)
HasChildViewState	Gets a value indicating whether the current server control's child controls have any saved view-state settings. (Inherited from Control)
HasFile	Gets a value indicating whether the FileUpload control contains a file.
HasFiles	Gets a value that indicates whether any files have been uploaded.
Height	Gets or sets the height of the Web server control. (Inherited from WebControl)
ID	Gets or sets the programmatic identifier assigned to the server control. (Inherited from Control)
IdSeparator	Gets the character used to separate control identifiers. (Inherited from Control)
IsChildControlStateCleared	Gets a value indicating whether controls contained within this control have control state. (Inherited from Control)
IsEnabled	Gets a value indicating whether the control is enabled. (Inherited from WebControl)
IsTrackingViewState	Gets a value that indicates whether the server control is saving changes to its view state. (Inherited from Control)
IsViewStateEnabled	Gets a value indicating whether view state is enabled for this control. (Inherited from Control)
LoadViewStateByID	Gets a value indicating whether the control participates in loading its view state by ID instead of index. (Inherited from Control)
NamingContainer	Gets a reference to the server control's naming container, which creates a unique namespace for differentiating between server controls with the same ID property value. (Inherited from Control)
Page	Gets a reference to the Page instance that contains the server control. (Inherited from Control)
Parent	Gets a reference to the server control's parent control in the page control hierarchy. (Inherited from Control)
PostedFile	Gets the underlying HttpPostedFile object for a file that is uploaded by using the FileUpload control.
PostedFiles	Gets the collection of uploaded files.
RenderingCompatibility	Gets a value that specifies the ASP.NET version that rendered HTML will be compatible with. (Inherited from Control)
Site	Gets information about the container that hosts the current control when rendered on a design surface. (Inherited from Control)
SkinID	Gets or sets the skin to apply to the control. (Inherited from WebControl)
Style	Gets a collection of text attributes that will be rendered as a style attribute on the outer tag of the Web server control. (Inherited from WebControl)
SupportsDisabledAttribute	Gets a value that indicates whether the control should set the `disabled` attribute of the rendered HTML element to "disabled" when the control's IsEnabled property is `false`. (Inherited from WebControl)
TabIndex	Gets or sets the tab index of the Web server control. (Inherited from WebControl)
TagKey	Gets the HtmlTextWriterTag value that corresponds to this Web server control. This property is used primarily by control developers. (Inherited from WebControl)
TagName	Gets the name of the control tag. This property is used primarily by control developers. (Inherited from WebControl)
TemplateControl	Gets or sets a reference to the template that contains this control. (Inherited from Control)
TemplateSourceDirectory	Gets the virtual directory of the Page or UserControl that contains the current server control. (Inherited from Control)
ToolTip	Gets or sets the text displayed when the mouse pointer hovers over the Web server control. (Inherited from WebControl)
UniqueID	Gets the unique, hierarchically qualified identifier for the server control. (Inherited from Control)
ValidateRequestMode	Gets or sets a value that indicates whether the control checks client input from the browser for potentially dangerous values. (Inherited from Control)
ViewState	Gets a dictionary of state information that allows you to save and restore the view state of a server control across multiple requests for the same page. (Inherited from Control)
ViewStateIgnoresCase	Gets a value that indicates whether the StateBag object is case-insensitive. (Inherited from Control)
ViewStateMode	Gets or sets the view-state mode of this control. (Inherited from Control)
Visible	Gets or sets a value that indicates whether a server control is rendered as UI on the page. (Inherited from Control)
Width	Gets or sets the width of the Web server control. (Inherited from WebControl)

Methods

AddAttributesToRender(HtmlTextWriter)	Adds the HTML attributes and styles of a FileUpload control to render to the specified HtmlTextWriter object.
AddedControl(Control, Int32)	Called after a child control is added to the Controls collection of the Control object. (Inherited from Control)
AddParsedSubObject(Object)	Notifies the server control that an element, either XML or HTML, was parsed, and adds the element to the server control's ControlCollection object. (Inherited from Control)
ApplyStyle(Style)	Copies any nonblank elements of the specified style to the Web control, overwriting any existing style elements of the control. This method is primarily used by control developers. (Inherited from WebControl)
ApplyStyleSheetSkin(Page)	Applies the style properties defined in the page style sheet to the control. (Inherited from Control)
BeginRenderTracing(TextWriter, Object)	Begins design-time tracing of rendering data. (Inherited from Control)
BuildProfileTree(String, Boolean)	Gathers information about the server control and delivers it to the Trace property to be displayed when tracing is enabled for the page. (Inherited from Control)
ClearCachedClientID()	Sets the cached ClientID value to `null`. (Inherited from Control)
ClearChildControlState()	Deletes the control-state information for the server control's child controls. (Inherited from Control)
ClearChildState()	Deletes the view-state and control-state information for all the server control's child controls. (Inherited from Control)
ClearChildViewState()	Deletes the view-state information for all the server control's child controls. (Inherited from Control)
ClearEffectiveClientIDMode()	Sets the ClientIDMode property of the current control instance and of any child controls to Inherit. (Inherited from Control)
CopyBaseAttributes(WebControl)	Copies the properties not encapsulated by the Style object from the specified Web server control to the Web server control that this method is called from. This method is used primarily by control developers. (Inherited from WebControl)
CreateChildControls()	Called by the ASP.NET page framework to notify server controls that use composition-based implementation to create any child controls they contain in preparation for posting back or rendering. (Inherited from Control)
CreateControlCollection()	Creates a new ControlCollection object to hold the child controls (both literal and server) of the server control. (Inherited from Control)
CreateControlStyle()	Creates the style object that is used internally by the WebControl class to implement all style related properties. This method is used primarily by control developers. (Inherited from WebControl)
DataBind()	Binds a data source to the invoked server control and all its child controls. (Inherited from Control)
DataBind(Boolean)	Binds a data source to the invoked server control and all its child controls with an option to raise the DataBinding event. (Inherited from Control)
DataBindChildren()	Binds a data source to the server control's child controls. (Inherited from Control)
Dispose()	Enables a server control to perform final clean up before it is released from memory. (Inherited from Control)
EndRenderTracing(TextWriter, Object)	Ends design-time tracing of rendering data. (Inherited from Control)
EnsureChildControls()	Determines whether the server control contains child controls. If it does not, it creates child controls. (Inherited from Control)
EnsureID()	Creates an identifier for controls that do not have an identifier assigned. (Inherited from Control)
Equals(Object)	Determines whether the specified object is equal to the current object. (Inherited from Object)
FindControl(String, Int32)	Searches the current naming container for a server control with the specified `id` and an integer, specified in the `pathOffset` parameter, which aids in the search. You should not override this version of the FindControl method. (Inherited from Control)
FindControl(String)	Searches the current naming container for a server control with the specified `id` parameter. (Inherited from Control)
Focus()	Sets input focus to a control. (Inherited from Control)
GetDesignModeState()	Gets design-time data for a control. (Inherited from Control)
GetHashCode()	Serves as the default hash function. (Inherited from Object)
GetRouteUrl(Object)	Gets the URL that corresponds to a set of route parameters. (Inherited from Control)
GetRouteUrl(RouteValueDictionary)	Gets the URL that corresponds to a set of route parameters. (Inherited from Control)
GetRouteUrl(String, Object)	Gets the URL that corresponds to a set of route parameters and a route name. (Inherited from Control)
GetRouteUrl(String, RouteValueDictionary)	Gets the URL that corresponds to a set of route parameters and a route name. (Inherited from Control)
GetType()	Gets the Type of the current instance. (Inherited from Object)
GetUniqueIDRelativeTo(Control)	Returns the prefixed portion of the UniqueID property of the specified control. (Inherited from Control)
HasControls()	Determines if the server control contains any child controls. (Inherited from Control)
HasEvents()	Returns a value indicating whether events are registered for the control or any child controls. (Inherited from Control)
IsLiteralContent()	Determines if the server control holds only literal content. (Inherited from Control)
LoadControlState(Object)	Restores control-state information from a previous page request that was saved by the SaveControlState() method. (Inherited from Control)
LoadViewState(Object)	Restores view-state information from a previous request that was saved with the SaveViewState() method. (Inherited from WebControl)
MapPathSecure(String)	Retrieves the physical path that a virtual path, either absolute or relative, maps to. (Inherited from Control)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
MergeStyle(Style)	Copies any nonblank elements of the specified style to the Web control, but will not overwrite any existing style elements of the control. This method is used primarily by control developers. (Inherited from WebControl)
OnBubbleEvent(Object, EventArgs)	Determines whether the event for the server control is passed up the page's UI server control hierarchy. (Inherited from Control)
OnDataBinding(EventArgs)	Raises the DataBinding event. (Inherited from Control)
OnInit(EventArgs)	Raises the Init event. (Inherited from Control)
OnLoad(EventArgs)	Raises the Load event. (Inherited from Control)
OnPreRender(EventArgs)	Raises the PreRender event for the FileUpload control.
OnUnload(EventArgs)	Raises the Unload event. (Inherited from Control)
OpenFile(String)	Gets a Stream used to read a file. (Inherited from Control)
RaiseBubbleEvent(Object, EventArgs)	Assigns any sources of the event and its information to the control's parent. (Inherited from Control)
RemovedControl(Control)	Called after a child control is removed from the Controls collection of the Control object. (Inherited from Control)
Render(HtmlTextWriter)	Sends the FileUpload control content to the specified HtmlTextWriter object, which writes the content to render on the client.
RenderBeginTag(HtmlTextWriter)	Renders the HTML opening tag of the control to the specified writer. This method is used primarily by control developers. (Inherited from WebControl)
RenderChildren(HtmlTextWriter)	Outputs the content of a server control's children to a provided HtmlTextWriter object, which writes the content to be rendered on the client. (Inherited from Control)
RenderContents(HtmlTextWriter)	Renders the contents of the control to the specified writer. This method is used primarily by control developers. (Inherited from WebControl)
RenderControl(HtmlTextWriter, ControlAdapter)	Outputs server control content to a provided HtmlTextWriter object using a provided ControlAdapter object. (Inherited from Control)
RenderControl(HtmlTextWriter)	Outputs server control content to a provided HtmlTextWriter object and stores tracing information about the control if tracing is enabled. (Inherited from Control)
RenderEndTag(HtmlTextWriter)	Renders the HTML closing tag of the control into the specified writer. This method is used primarily by control developers. (Inherited from WebControl)
ResolveAdapter()	Gets the control adapter responsible for rendering the specified control. (Inherited from Control)
ResolveClientUrl(String)	Gets a URL that can be used by the browser. (Inherited from Control)
ResolveUrl(String)	Converts a URL into one that is usable on the requesting client. (Inherited from Control)
SaveAs(String)	Saves the contents of an uploaded file to a specified path on the Web server.
SaveControlState()	Saves any server control state changes that have occurred since the time the page was posted back to the server. (Inherited from Control)
SaveViewState()	Saves any state that was modified after the TrackViewState() method was invoked. (Inherited from WebControl)
SetDesignModeState(IDictionary)	Sets design-time data for a control. (Inherited from Control)
SetRenderMethodDelegate(RenderMethod)	Assigns an event handler delegate to render the server control and its content into its parent control. (Inherited from Control)
SetTraceData(Object, Object, Object)	Sets trace data for design-time tracing of rendering data, using the traced object, the trace data key, and the trace data value. (Inherited from Control)
SetTraceData(Object, Object)	Sets trace data for design-time tracing of rendering data, using the trace data key and the trace data value. (Inherited from Control)
ToString()	Returns a string that represents the current object. (Inherited from Object)
TrackViewState()	Causes the control to track changes to its view state so they can be stored in the object's ViewState property. (Inherited from WebControl)

Events

DataBinding	Occurs when the server control binds to a data source. (Inherited from Control)
Disposed	Occurs when a server control is released from memory, which is the last stage of the server control lifecycle when an ASP.NET page is requested. (Inherited from Control)
Init	Occurs when the server control is initialized, which is the first step in its lifecycle. (Inherited from Control)
Load	Occurs when the server control is loaded into the Page object. (Inherited from Control)
PreRender	Occurs after the Control object is loaded but prior to rendering. (Inherited from Control)
Unload	Occurs when the server control is unloaded from memory. (Inherited from Control)

Explicit Interface Implementations

IAttributeAccessor.GetAttribute(String)	Gets an attribute of the Web control with the specified name. (Inherited from WebControl)
IAttributeAccessor.SetAttribute(String, String)	Sets an attribute of the Web control to the specified name and value. (Inherited from WebControl)
IControlBuilderAccessor.ControlBuilder	For a description of this member, see ControlBuilder. (Inherited from Control)
IControlDesignerAccessor.GetDesignModeState()	For a description of this member, see GetDesignModeState(). (Inherited from Control)
IControlDesignerAccessor.SetDesignModeState(IDictionary)	For a description of this member, see SetDesignModeState(IDictionary). (Inherited from Control)
IControlDesignerAccessor.SetOwnerControl(Control)	For a description of this member, see SetOwnerControl(Control). (Inherited from Control)
IControlDesignerAccessor.UserData	For a description of this member, see UserData. (Inherited from Control)
IDataBindingsAccessor.DataBindings	For a description of this member, see DataBindings. (Inherited from Control)
IDataBindingsAccessor.HasDataBindings	For a description of this member, see HasDataBindings. (Inherited from Control)
IExpressionsAccessor.Expressions	For a description of this member, see Expressions. (Inherited from Control)
IExpressionsAccessor.HasExpressions	For a description of this member, see HasExpressions. (Inherited from Control)
IParserAccessor.AddParsedSubObject(Object)	For a description of this member, see AddParsedSubObject(Object). (Inherited from Control)

Extension Methods

FindDataSourceControl(Control)	Returns the data source that is associated with the data control for the specified control.
FindFieldTemplate(Control, String)	Returns the field template for the specified column in the specified control's naming container.
FindMetaTable(Control)	Returns the metatable object for the containing data control.

Applies to

Dela via