/// <summary>
/// The method that is called when the PreviewCanExecute <see cref="RoutedEvent" /> for the
/// <see cref="ICommand" /> associated with this <see cref="DataContextCommandBinding" />
/// should be handled.
/// </summary>
/// <param name="sender">The command target on which the command is executing.</param>
/// <param name="e">The event data.</param>
protected internal override void OnPreviewCanExecute(object sender, CanExecuteRoutedEventArgs e)
{
if (e == null)
{
throw new ArgumentNullException("e");
}
var target = DataContext.GetDataContext(sender);
bool canExecute;
if (
!CommandExecutionManager.TryExecuteCommand(
target,
e.Parameter,
false,
PreviewExecuted,
PreviewCanExecute,
out canExecute))
{
return;
}
e.CanExecute = canExecute;
e.Handled = true;
}
bool ICommand.CanExecute(object parameter)
{
var target = GetDataContext(this._target);
if (this._target == null)
{
return(false);
}
bool canExecute;
return(CommandExecutionManager.TryExecuteCommand(target, parameter, false, this.Executed, this.CanExecute, out canExecute) && canExecute);
}
void ICommand.Execute(object parameter)
{
var target = GetDataContext(this._target);
if (this._target == null)
{
return;
}
bool canExecute;
CommandExecutionManager.TryExecuteCommand(target, parameter, true, this.Executed, this.CanExecute, out canExecute);
}
/// <summary>
/// The method that is called when the Executed <see cref="RoutedEvent" /> for the
/// <see cref="ICommand" /> associated with this <see cref="DataContextCommandBinding" />
/// should be handled.
/// </summary>
/// <param name="sender">The command target on which the command is executing.</param>
/// <param name="e">The event data.</param>
protected internal override void OnExecuted(object sender, ExecutedRoutedEventArgs e)
{
if (e == null)
{
throw new ArgumentNullException("e");
}
var target = DataContext.GetDataContext(sender);
bool canExecute;
if (CommandExecutionManager.TryExecuteCommand(
target,
e.Parameter,
true,
Executed,
CanExecute,
out canExecute))
{
e.Handled = true;
}
}