CODEWITHSUNDEEP
c#wpfcommand
Nike
Nike

Reputation: 1357

WPF: How to redefine CanExecute method of ApplicationCommands

I use standard Cut, Copy and Paste commands (which is part of ApplicationCommands class). Is it possible to redefine CanExecute method?

Here is my code:

XAML:

   <Window.CommandBindings>
        <CommandBinding Command="Copy"
                CanExecute="CopyCanExecute" Executed="CopyExecuted"/>       
    </Window.CommandBindings>

    <StackPanel>
        <TextBox Name="txt"></TextBox>
        <Button Command="Copy" CommandTarget="{Binding ElementName=txt}">copy</Button>
    </StackPanel>

Code-behind:

private void CopyCanExecute(object sender, CanExecuteRoutedEventArgs e)
{
    e.CanExecute = false;
}

private void CopyExecuted(object sender, ExecutedRoutedEventArgs e)
{
    MessageBox.Show("Copy Executed");
}

The button still behave like its command is standard Copy command.

Upvotes: 3

Views: 3606

Answers (4)

Oliver Hauck
Oliver Hauck

Reputation: 71

You can set the commandbinding to the textbox directly instead of to the window.

Upvotes: 0

Ascii
Ascii

Reputation: 21

The copy command will not work when the focus is on a textbox where the commands have already been handled, but it will work on elements like CheckBox etc.

Upvotes: 1

Jobi Joy
Jobi Joy

Reputation: 50038

In the CanExecute handler you might need to add `e.Handled = true; also, so that it doesnt go and execute the standard Copy.CanExecute()

Upvotes: 0

Reed Copsey
Reed Copsey

Reputation: 564413

You do this via a CommandBinding. The local CommandBinding can specify a CanExecuteHandler.

For details and a working example, see this blog post.

Upvotes: 1

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