CODEWITHSUNDEEP
c#wpfrouted-commands
Billy ONeal
Billy ONeal

Reputation: 106549

Why does command binding to a button have different behavior than command binding a menu item?

Consider the following example with a menu and a button:

<Window x:Class="WpfApplication1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
  <DockPanel>
    <Menu DockPanel.Dock="Top">
      <MenuItem Header="Paste" Command="ApplicationCommands.Paste" />
    </Menu>
    <Button Command="ApplicationCommands.Paste">Paste</Button>
    <TextBox>Content</TextBox>
    <TextBox>Content2</TextBox>
  </DockPanel>
</Window>

When I put keyboard focus in one of the text boxes, the TextBox declares that it can handle ApplicationCommands.Paste, and so I expect the button and the menu item to enable themselves. What I get instead is that the menu item enables itself, and the button does not. (The button doesn't appear to be "listening" to the TextBox' CommandBinding)

What's going on here, and is there any way I can work around this?

EDIT: I did find this question --> WPF routed command enabling works with menu but not with a button <-- but this is not suitable in this case. The button should not be keyboard focusable, and setting it as a focus scope makes it focusable. I can't bind the source, because the actual source needs to be controlled by keyboard focus.

Upvotes: 2

Views: 160

Answers (1)

Terry Lewis
Terry Lewis

Reputation: 407

It appears that you can't use the Command property of a button in this manner unless it's contained in a Toolbar. I get the same results you do with your xaml, but I use the same code regularly to assign this command to a button in a toolbar.

See Copy and paste commands with WPF buttons for more information.

EDIT:

You're right. It has to do with the FocusScope, and there are two ways to fix it, as shown here:

WPF routed command enabling works with menu but not with a button

You can set FocusManager.IsFocusScope on the button:

<Button Command="ApplicationCommands.Paste" FocusManager.IsFocusScope="True">Paste</Button>

Alternately, you can set the button's command target, but this will only work for one textbox.

Upvotes: 1

Related Questions