OpenFileDialog.Multiselect Property

Definition

Namespace:

System.Windows.Forms

Assembly:

System.Windows.Forms.dll

Source:

OpenFileDialog.cs

Gets or sets a value indicating whether the dialog box allows multiple files to be selected.

public:
 property bool Multiselect { bool get(); void set(bool value); };

public bool Multiselect { get; set; }

member this.Multiselect : bool with get, set

Public Property Multiselect As Boolean

Property Value

Boolean

true if the dialog box allows multiple files to be selected together or concurrently; otherwise, false. The default value is false.

Examples

The following code example allows the user to select a number of images and display them in PictureBox controls on a Form. It demonstrates initializing an OpenFileDialog, setting the Title and Filter properties, and allowing the user to select multiple files by setting the Multiselect property to true. This code example assumes that your form already has an OpenFileDialog control named openFileDialog1, a Button named SelectFileButton, and a FlowLayoutPanel named flowLayoutPanel1.

private void Form1_Load(object sender, EventArgs e)
{
    InitializeOpenFileDialog();
}

private void InitializeOpenFileDialog()
{
    // Set the file dialog to filter for graphics files.
    this.openFileDialog1.Filter =
        "Images (*.BMP;*.JPG;*.GIF)|*.BMP;*.JPG;*.GIF|" +
        "All files (*.*)|*.*";

    // Allow the user to select multiple images.
    this.openFileDialog1.Multiselect = true;
    this.openFileDialog1.Title = "My Image Browser";
}

private void selectFilesButton_Click(object sender, EventArgs e)
{
    DialogResult dr = this.openFileDialog1.ShowDialog();
    if (dr == System.Windows.Forms.DialogResult.OK)
    {
        // Read the files
        foreach (String file in openFileDialog1.FileNames) 
        {
            // Create a PictureBox.
            try
            {
                PictureBox pb = new PictureBox();
                Image loadedImage = Image.FromFile(file);
                pb.Height = loadedImage.Height;
                pb.Width = loadedImage.Width;
                pb.Image = loadedImage;
                flowLayoutPanel1.Controls.Add(pb);
            }
            catch (SecurityException ex)
            {
                // The user lacks appropriate permissions to read files, discover paths, etc.
                MessageBox.Show("Security error. Please contact your administrator for details.\n\n" +
                    "Error message: " + ex.Message + "\n\n" +
                    "Details (send to Support):\n\n" + ex.StackTrace
                );
            }
            catch (Exception ex)
            {
                // Could not load the image - probably related to Windows file system permissions.
                MessageBox.Show("Cannot display the image: " + file.Substring(file.LastIndexOf('\\'))
                    + ". You may not have permission to read the file, or " +
                    "it may be corrupt.\n\nReported error: " + ex.Message);
            }
        }
    }

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    InitializeOpenFileDialog()
End Sub

Private Sub SelectFileButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles SelectFileButton.Click
    Dim dr As DialogResult = Me.OpenFileDialog1.ShowDialog()
    If (dr = System.Windows.Forms.DialogResult.OK) Then
        ' Read the files
        Dim file As String
        For Each file In OpenFileDialog1.FileNames
            ' Create a PictureBox for each file, and add that file to the FlowLayoutPanel.
            Try
                Dim pb As New PictureBox()
                Dim loadedImage As Image = Image.FromFile(file)
                pb.Height = loadedImage.Height
                pb.Width = loadedImage.Width
                pb.Image = loadedImage
                FlowLayoutPanel1.Controls.Add(pb)
            Catch SecEx As SecurityException
                ' The user lacks appropriate permissions to read files, discover paths, etc.
                MessageBox.Show("Security error. Please contact your administrator for details.\n\n" & _
                    "Error message: " & SecEx.Message & "\n\n" & _
                    "Details (send to Support):\n\n" & SecEx.StackTrace)
            Catch ex As Exception
                ' Could not load the image - probably permissions-related.
                MessageBox.Show(("Cannot display the image: " & file.Substring(file.LastIndexOf("\"c)) & _
                ". You may not have permission to read the file, or " + "it may be corrupt." _
                & ControlChars.Lf & ControlChars.Lf & "Reported error: " & ex.Message))
            End Try
        Next file
    End If
End Sub

Public Sub InitializeOpenFileDialog()
    ' Set the file dialog to filter for graphics files.
    Me.OpenFileDialog1.Filter = _
            "Images (*.BMP;*.JPG;*.GIF)|*.BMP;*.JPG;*.GIF|" + _
            "All files (*.*)|*.*"

    ' Allow the user to select multiple images.
    Me.OpenFileDialog1.Multiselect = True
    Me.OpenFileDialog1.Title = "My Image Browser"
End Sub

Remarks

Use the FileNames property to access the full list of selected file names.

See also

• FileNames
• Filter