/**
* Overridden to preserve usual semantics: returns true if an undo
* operation would be successful now, false otherwise
*/
public override bool CanUndo()
{
if (inProgress)
{
IUndoableEdit edit = EditToBeUndone();
return(edit != null && edit.CanUndo());
}
else
{
return(base.CanUndo());
}
}
public override bool CanUndo()
{
lock (this) {
if (IsInProgress())
{
IUndoableEdit e = EditToBeUndone();
return(e != null && e.CanUndo());
}
else
{
return(base.CanUndo());
}
}
}
/// <summary>
/// This predicate is true when one can call <see cref="Undo"/>.
/// </summary>
/// <returns></returns>
/// <remarks>
/// In order to be able to perform an undo, a transaction must not
/// be in progress, nor an undo or a redo.
/// Furthermore there must be an <see cref="EditToUndo"/> that itself
/// is ready to be undone, because its <see cref="IUndoableEdit.CanUndo"/>
/// predicate is true.
/// </remarks>
/// <seealso cref="Undo"/>
public virtual bool CanUndo()
{
if (this.TransactionLevel > 0)
{
return(false);
}
if (this.IsUndoingRedoing)
{
return(false);
}
IUndoableEdit curr = this.EditToUndo;
return(curr != null && curr.CanUndo());
}
public virtual bool CanUndo()
{
if (this.TransactionLevel <= 0)
{
if (this.IsUndoing)
{
return(false);
}
if (this.IsRedoing)
{
return(false);
}
IUndoableEdit edit1 = this.EditToUndo;
if (edit1 != null)
{
return(edit1.CanUndo());
}
}
return(false);
}