OpenFileDialog.ShowReadOnly Property


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Gets or sets a value indicating whether the dialog box contains a read-only check box.

Namespace:   System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

public bool ShowReadOnly { get; set; }

Property Value

Type: System.Boolean

true if the dialog box contains a read-only check box; otherwise, false. The default value is false.

The following code example demonstrates the use of the ShowReadOnly property. This example displays the OpenFileDialog box with the ShowReadOnly property set to true. If the user clicks the option to open the file in read-only mode, the OpenFile method is used to open the file. Otherwise, the FileStream class is used to open the file in read/write mode.

private FileStream OpenFile()
    // Displays an OpenFileDialog and shows the read/only files.

    OpenFileDialog dlgOpenFile = new OpenFileDialog();
    dlgOpenFile.ShowReadOnly = true;

    if(dlgOpenFile.ShowDialog() == DialogResult.OK)

        // If ReadOnlyChecked is true, uses the OpenFile method to
        // open the file with read/only access.
        string path = null;

        try {
            if(dlgOpenFile.ReadOnlyChecked == true)
                return (FileStream)dlgOpenFile.OpenFile();

            // Otherwise, opens the file with read/write access.
                path = dlgOpenFile.FileName;
                return new FileStream(path, System.IO.FileMode.Open,
        } 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: " + path.Substring(path.LastIndexOf('\\'))
                    + ". You may not have permission to read the file, or " +
                    "it may be corrupt.\n\nReported error: " + ex.Message);

    return null;

.NET Framework
Available since 1.1
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