FileUpload.PostedFile 属性

参考

定义

命名空间:: System.Web.UI.WebControls

程序集:: System.Web.dll

重要

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获取使用 FileUpload 控件上载的文件的基础 HttpPostedFile 对象。

public:
 property System::Web::HttpPostedFile ^ PostedFile { System::Web::HttpPostedFile ^ get(); };

[System.ComponentModel.Browsable(false)]
public System.Web.HttpPostedFile PostedFile { get; }

[<System.ComponentModel.Browsable(false)>]
member this.PostedFile : System.Web.HttpPostedFile

Public ReadOnly Property PostedFile As HttpPostedFile

属性值

HttpPostedFile

使用 FileUpload 上载的文件的 HttpPostedFile。

属性: BrowsableAttribute

示例

以下示例演示如何创建 FileUpload 控件。当用户单击 “Upload文件”按钮时，文件的内容会显示为页面上的文本框中的字节。此示例使用 PostedFile 属性访问 HttpPostedFile.ContentLength 该属性。属性 ContentLength 用于在将文件内容复制到字节数组之前确定文件的长度。

<%@ 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)
        {
            // Append the name of the file to upload to the path.
            savePath += 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.";
                
            // Call a helper routine to display the contents
            // of the file to upload.
            DisplayFileContents(FileUpload1.PostedFile);
        }
        else
        {
            // Notify the user that a file was not uploaded.
            UploadStatusLabel.Text = "You did not specify a file to upload.";
        }
    }
    void DisplayFileContents(HttpPostedFile file)
    {
        System.IO.Stream myStream;
        Int32 fileLen;
        StringBuilder displayString = new StringBuilder();
     
        // Get the length of the file.
        fileLen = FileUpload1.PostedFile.ContentLength;
            
        // Display the length of the file in a label.
        LengthLabel.Text = "The length of the file is " + 
                           fileLen.ToString() + " bytes.";
   
        // Create a byte array to hold the contents of the file.
        Byte[] Input = new Byte[fileLen];
            
        // Initialize the stream to read the uploaded file.
        myStream = FileUpload1.FileContent;
            
        // Read the file into the byte array.
        myStream.Read(Input, 0, fileLen);
        
        // Copy the byte array to a string.
        for (int loop1 = 0; loop1 < fileLen; loop1++)
        {
            displayString.Append(Input[loop1].ToString());
        }

        // Display the contents of the file in a 
        // textbox on the page.
        ContentsLabel.Text = "The contents of the file as bytes:";

        TextBox ContentsTextBox = new TextBox();
        ContentsTextBox.TextMode = TextBoxMode.MultiLine;
        ContentsTextBox.Height = Unit.Pixel(300);
        ContentsTextBox.Width = Unit.Pixel(400);
        ContentsTextBox.Text = displayString.ToString();

        // Add the textbox to the Controls collection
        // of the Placeholder control.
        PlaceHolder1.Controls.Add(ContentsTextBox);

    }
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>FileUpload.FileContent Property 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>
        
        <br /><br />
        
        <asp:Label id="UploadStatusLabel"
           runat="server">
        </asp:Label>  
            
        <hr />
        
        <asp:Label id="LengthLabel"
           runat="server">
        </asp:Label>  
        
        <br /><br />
       
        <asp:Label id="ContentsLabel"
           runat="server">
        </asp:Label>  
        
        <br /><br />
       
        <asp:PlaceHolder id="PlaceHolder1"
            runat="server">
        </asp:PlaceHolder>        
    </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
            
            ' Append the name of the file to upload to the path.
            savePath += 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."
                
            ' Call a helper routine to display the contents
            ' of the file to upload.
            DisplayFileContents(FileUpload1.PostedFile)
        Else
            ' Notify the user that a file was not uploaded.
            UploadStatusLabel.Text = "You did not specify a file to upload."
        End If

    End Sub

    Sub DisplayFileContents(ByVal file As HttpPostedFile)
            
        Dim myStream As System.IO.Stream
        Dim fileLen As Integer
        Dim displayString As New StringBuilder()
        Dim loop1 As Integer
            
        ' Get the length of the file.
        fileLen = FileUpload1.PostedFile.ContentLength
            
        ' Display the length of the file in a label.
        LengthLabel.Text = "The length of the file is " _
                           + fileLen.ToString + " bytes."
            
        ' Create a byte array to hold the contents of the file.
        Dim Input(fileLen) As Byte
            
        ' Initialize the stream to read the uploaded file.
        myStream = FileUpload1.FileContent
            
        ' Read the file into the byte array.
        myStream.Read(Input, 0, fileLen)
            
        ' Copy the byte array to a string.
        For loop1 = 0 To fileLen - 1
            displayString.Append(Input(loop1).ToString())
        Next loop1
            
        ' Display the contents of the file in a 
        ' textbox on the page.
        ContentsLabel.Text = "The contents of the file as bytes:"
            
        Dim ContentsTextBox As New TextBox
        ContentsTextBox.TextMode = TextBoxMode.MultiLine
        ContentsTextBox.Height = Unit.Pixel(300)
        ContentsTextBox.Width = Unit.Pixel(400)
        ContentsTextBox.Text = displayString.ToString()
            
        ' Add the textbox to the Controls collection
        ' of the Placeholder control.
        PlaceHolder1.Controls.Add(ContentsTextBox)

    End Sub
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>FileUpload.FileContent Property 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>
        
        <br /><br />
        
        <asp:Label id="UploadStatusLabel"
           runat="server">
        </asp:Label>  
            
        <hr />
        
        <asp:Label id="LengthLabel"
           runat="server">
        </asp:Label>  
        
        <br /><br />
       
        <asp:Label id="ContentsLabel"
           runat="server">
        </asp:Label>  
        
        <br /><br />
       
        <asp:PlaceHolder id="PlaceHolder1"
            runat="server">
        </asp:PlaceHolder>        
    </div>
    </form>
</body>
</html>

注解

该PostedFile属性获取通过使用FileUpload控件上传的文件的基础HttpPostedFile对象。使用此属性访问上传文件上的其他属性。

可以使用该 ContentLength 属性获取文件的长度。可以使用该 ContentType 属性获取文件的 MIME 内容类型。此外，可以使用 PostedFile 该属性访问 FileName 属性、 InputStream 属性和 SaveAs 方法。但是，属性、FileContent属性和SaveAs方法提供了FileName相同的功能。

适用于

另请参阅

HttpPostedFile

通过

FileUpload.PostedFile 属性

定义

属性值

示例

注解

适用于

另请参阅

其他资源