CanUndo Method

CanUndo()

Declaration

public bool CanUndo()

Public Function CanUndo() As Boolean

Returns

Examples

This example shows how to create a custom context menu that can be linked to a C1Editor control and has Undo and Redo buttons.

class MyContextMenuStrip : ContextMenuStrip
{
private C1Editor _owner;
private ToolStripMenuItem _btnUndo, _btnRedo;
            public MyContextMenuStrip(C1Editor editor)
            {
                // save reference to parent control
                _owner = editor;

                // create menu items
                _btnUndo = (ToolStripMenuItem)Items.Add("Undo");
                _btnUndo.ShortcutKeys = Keys.Control | Keys.Z;
                _btnRedo = (ToolStripMenuItem)Items.Add("Redo");
                _btnRedo.ShortcutKeys = Keys.Control | Keys.Y;
            }

            protected override void OnItemClicked(ToolStripItemClickedEventArgs e)
            {
                Close();

                if (e.ClickedItem == _btnUndo)
                    _owner.Undo();
                else if (e.ClickedItem == _btnRedo)
                    _owner.Redo();
                base.OnItemClicked(e);
            }

            protected override void OnOpening(System.ComponentModel.CancelEventArgs e)
            {
                _btnUndo.Enabled = _owner.CanUndo;
                _btnRedo.Enabled = _owner.CanCut;
                base.OnOpening(e);
            }</code></pre>