WPF KeyBinding on Page in Frame (in TabControl)

Question

I have a WPF Window containing a TabControl, which has Frames in it which display Pages. Like this:

<Window x:Class="MyNamespace.View.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow">
    <DockPanel>
        <TabControl x:Name="TabControl">
            <TabItem Header="StartScreen" x:Name="StartScreenTab">
                <Frame Source="StartScreenPage.xaml"/>
            </TabItem>
            <TabItem Header="OtherTab" x:Name="OtherTab">
                <Frame Source="OtherPage.xaml"/>
            </TabItem>
        </TabControl>
    </DockPanel>
</Window>

In one of the pages, I have a KeyBinding:

<Page x:Class="MyNamespace.View.OtherPage"
      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
      xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
      mc:Ignorable="d" 
      Title="OtherPage">
    <Page.InputBindings>
        <KeyBinding Key="U" Modifiers="Control" Command="{Binding MyCommand}"/>
    </Page.InputBindings>
    <!-- Content ... -->
</Page>

MyCommand is a property of OtherPage.DataContext, it's only available from the page, not available from outside.

My problem is that the KeyBinding only works after I click on a control inside the Page. I want that KeyBinding to work whenever OtherPage is visible, equivalently when OtherTab is the active tab. How can I achieve this?

Possible duplicate of [InputBindings work only when focused](https://stackoverflow.com/questions/23316274/inputbindings-work-only-when-focused) — Jan, Sep 20 '18 at 08:39

score 1 · Answer 1 · answered Jul 02 '14 at 13:15

The only way that you can achieve that is to move your KeyBinding and the ICommand implementation to the MainWindow.xaml file:

<Window.InputBindings>
    <KeyBinding Key="U" Modifiers="Control" Command="{Binding MyCommand}"/>
</Window.InputBindings>

If you can't move the actual implementation of the ICommand, then you must at least make it accessible from there.

score 1 · Accepted Answer · edited May 23 '17 at 12:29

I did something similar to what Sheridan recommended in his answer.

In MainWindow.xaml I declare a RoutedUICommand:

<Window x:Class="MyNamespace.View.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow">
    <Window.Resources>
        <ResourceDictionary>
            <RoutedUICommand x:Key="OtherPageCommand"/>
        </ResourceDictionary>
    </Window.Resources>
    <Window.CommandBindings>
        <CommandBinding Command="{StaticResource OtherPageCommand}"
                        Executed="OtherPageCommandExecuted"/>
    </Window.CommandBindings>
    <Window.InputBindings>
        <KeyBinding Key="U" Modifiers="Control" Command="{StaticResource OtherPageCommand}"/>
    </Window.InputBindings>
<DockPanel>
        <TabControl x:Name="TabControl">
            <TabItem Header="StartScreen" x:Name="StartScreenTab">
                <Frame Source="StartScreenPage.xaml"/>
            </TabItem>
            <TabItem Header="OtherTab" x:Name="OtherTab">
                <Frame Source="OtherPage.xaml"/>
            </TabItem>
        </TabControl>
    </DockPanel>
</Window>

In MainWindow.xaml.cs I have this method:

    private void OtherPageCommandExecuted(object sender, ExecutedRoutedEventArgs e)
    {
        var page = ((Frame)((TabItem) TabControl.SelectedItem).Content).Content as OtherPage;
        if (page != null)
        {
            var viewModel = page.DataContext as MyViewModel;
            if (viewModel != null)
            {
                var openWindow = viewModel.MyCommand;
                var parameter = null; // put your command parameter here
                if (openWindow.CanExecute(parameter))
                    openWindow.Execute(parameter);
            }
        }
    }

This way I propagate the keybinding to the page but the actual command remains in the viewmodel of the page.

WPF KeyBinding on Page in Frame (in TabControl)

2 Answers2