Many of the commands described above may or may not be available depending on whether a document is currently loaded, the selection state, or the clipboard content. If a command is not available, it should be disabled in the tool strip.

The ToolStripMain class handles this by overriding the UpdateState method as follows:

To write code in C#

public override void UpdateState()
{
    Enabled = Editor != null;
    _btnCopy.Enabled = _btnCut.Enabled = Editor.CanCopy;
    _btnPaste.Enabled = Editor.CanPasteAsText; // CanPaste
    _btnUndo.Enabled = Editor.CanUndo();
    _btnRedo.Enabled = Editor.CanRedo();
    _btnSpell.Enabled = _btnShowErrors.Enabled = SpellChecker != null;
}

The implementation is self-explanatory. The C1Editor provides properties and methods that allow the toolstrip to update itself very easily.