Clipboard Access Policy
- 6 minutes to read
The DevExpress.Data.Utils.ClipboardAccessPolicy allows you to control/manage clipboard-related operations when using DevExpress UI controls (within Windows Forms and WPF applications).
Apply a Policy
Use the following methods to apply a policy (call these methods at application startup):
- SuppressAllOperations() – Applies a policy to suppress all clipboard-related operations within DevExpress WinForms and WPF controls.
- SuppressCopyOperations() – Applies a policy to suppress all copy-to-clipboard operations within DevExpress UI controls.
- SuppressPasteOperations() – Applies a policy to suppress all paste-from-clipboard operations within DevExpress UI controls.
- SuppressClearOperations() – Applies a policy to suppress clipboard clear operations within DevExpress UI controls.
- SuppressContainsOperations() – Applies a policy to suppress clipboard-access operations performed by DevExpress WinForms and WPF controls.
- ThrowAlways() – Applies a policy to suppress all clipboard-related operations in DevExpress UI controls. Raises an exception when a user or UI control attempts to initiate a clipboard-related operation.
- ThrowOnErrors() – Applies a policy to throw an exception when a clipboard-related operation fails within a DevExpress UI control.
The following example allows users to copy data in ANSI text format (when displayed in a DevExpress UI control) to the clipboard. If the control displays data in a different format, the copy-to-clipboard operation is canceled:
using System;
using System.Windows.Forms;
using DevExpress.Data.Utils;
namespace DXApplication {
internal static class Program {
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main() {
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
ClipboardAccessPolicy.SuppressCopyOperations();
Application.Run(new Form1());
}
}
}
Manage Copy/Paste/Clear Clipboard Operations using Events
Handle the following events in the ClipboardAccessPolicy class to configure policy settings:
The following example allows a user to paste data in ANSI text format within a DevExpress UI control (from the clipboard). If the user pastes data in a different format, the paste-from-clipboard operation is canceled:
using System;
using System.Windows.Forms;
using DevExpress.Data.Utils;
namespace DXApplication {
internal static class Program {
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main() {
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
ClipboardAccessPolicy.SuppressCopyOperations();
ClipboardAccessPolicy.Pasting += ClipboardAccessPolicy_Pasting;
Application.Run(new Form1());
}
private static void ClipboardAccessPolicy_Pasting(object sender, ClipboardAccessPolicy.ClipboardOperationRequestEventArgs e) {
if (e.DataFormat == DataFormats.Text)
e.Cancel = false;
}
}
}
Handle Exceptions
DevExpress UI controls catch clipboard-related errors or exceptions (error swallowing), and then continue without logging, processing, or reporting errors. Call the ThrowOnErrors() method at application startup to manually handle clipboard-related errors. The method applies a policy that allows all clipboard-related operations. The policy throws an exception when a clipboard-related operation fails in a DevExpress WinForms or WPF control.
You can also use the ThrowAlways method to apply a policy that disables all clipboard-related operations (copy, paste, clear) in DevExpress WinForms and WPF controls. The policy throws an exception when a user or UI control attempts to initiate a clipboard-related operation.
Tip
Use AllowOperation and/or AllowDataFormats methods to enable specific operations for all (or specific) data formats when a restrictive policy is enabled.
Important
SuppressAllOperations(), SuppressCopyOperations(), SuppressPasteOperations(), SuppressClearOperations(), and SuppressContainsOperations() policies take priority over AllowOperation and AllowDataFormats.
Handle the Failed event to respond to associated failures.
Example 1
The following example introduces a policy that allows a user to copy text to the clipboard and disallows other clipboard-related operations. If the user or a control attempts to execute a disallowed operation, the policy throws an exception.
using System;
using System.Windows.Forms;
using DevExpress.Data.Utils;
using DevExpress.Data.Internal;
namespace DXApplication {
internal static class Program {
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main() {
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
ClipboardAccessPolicy.AllowOperation(ClipboardOperation.Copy, DataFormats.Text);
ClipboardAccessPolicy.ThrowAlways();
Application.Run(new Form1());
}
}
}
Example 2: Allow Specific Operations
using System;
using System.Windows.Forms;
using DevExpress.Data.Utils;
namespace DXApplication {
internal static class Program {
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main() {
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
ClipboardAccessPolicy.ThrowAlways();
ClipboardAccessPolicy.Failed += ClipboardAccessPolicy_Failed;
Application.Run(new Form1());
}
private static void ClipboardAccessPolicy_Failed(object sender, ClipboardAccessPolicy.FailedEventArgs e) {
if (e.DataFormat == DataFormats.Text)
e.Throw = false;
}
}
}
Example 3: Handle Internal Exceptions
The following example suppresses an internal exception and displays a message box:
using System;
using System.Windows.Forms;
using DevExpress.Data.Utils;
using DevExpress.XtraEditors;
namespace DXApplication11 {
internal static class Program {
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main() {
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
ClipboardAccessPolicy.ThrowAlways();
ClipboardAccessPolicy.Failed += ClipboardAccessPolicy_Failed;
Application.Run(new Form1());
}
private static void ClipboardAccessPolicy_Failed(object sender, ClipboardAccessPolicy.FailedEventArgs e) {
e.Throw = false;
XtraMessageBox.Show(String.Format("{0} operation is not allowed.", e.Operation.ToString()), "Warning");
}
}
}