private void Push(T item)
{
Debug.Assert(_stack.Count == 0 || _stack[_stack.Count - 1] != item);
_stack.Add(item);
NotifyOfPropertyChange("Previous");
if (_stack.Count == 2)
{
GoBackCmd.RaiseCanExecuteChanged(_goBackCommand);
}
}
private void Pop()
{
Debug.Assert(_stack.Count > 1, "We never pop the root page.");
_stack.RemoveAt(_stack.Count - 1);
NotifyOfPropertyChange("Previous");
if (_stack.Count == 1)
{
GoBackCmd.RaiseCanExecuteChanged(_goBackCommand);
}
}
static public GoBackCmd Ensure(StackConductor <T> holder, ref WeakReference <GoBackCmd> cmdRef)
{
GoBackCmd cmd;
if (cmdRef == null)
{
cmdRef = cmd = new GoBackCmd(holder);
}
else if ((cmd = cmdRef.Target) == null)
{
cmdRef.Target = cmd = new GoBackCmd(holder);
}
return(cmd);
}