箭头键绑定不触发

Question

I'm trying to get the four arrow keys to be bound to a command in my ViewModel , but they are not working. I have a ContentControl in a Window with InputBindings like so:

<ContentControl.InputBindings>
    <KeyBinding Command="{Binding EndCmd}" Key="Esc" />
    <KeyBinding Command="{Binding PanUpCmd}" Key="Up" />
    <KeyBinding Command="{Binding PanDownCmd}" Key="Down" />
    <KeyBinding Command="{Binding PanLeftCmd}" Key="Left" />
    <KeyBinding Command="{Binding PanRightCmd}" Key="Right" />
</ContentControl.InputBindings>

In my ViewModel :

public RelayCommand EndCmd { get; set; }
public RelayCommand PanUpCmd { get; set; }
public RelayCommand PanDownCmd { get; set; }
public RelayCommand PanLeftCmd { get; set; }
public RelayCommand PanRightCmd { get; set; }

public MainViewModel()
{
    EndCmd = new RelayCommand(End);
    PanUpCmd = new RelayCommand(PanUp);
    PanDownCmd = new RelayCommand(PanDown);
    PanLeftCmd = new RelayCommand(PanLeft);
    PanRightCmd = new RelayCommand(PanRight);
}

//functions that the commands call here

Now, the Escape key works fine, but the four arrow keys do not. Why is this? They are set up exactly the same. I thought maybe it was something to do with the DataContext so I put the KeyBinding s in the Window s InputBindings` but it was the same issue.

Edit: I've tested every key on my keyboard. Every key fires properly except the four arrow keys. I checked if the Content of the ContentControl was swallowing the events, and it was not. In fact, the Control that is the Content has it's own keydown event, which is also never called, nor is the previewkeydown, with the arrow keys.

Answer 1

I copied your code and it seems to work fine.

The only reason I can think for this not to work in your case (especially if Esc works, but not the other keys) is that whatever content you're using inside of the ContentControl also contains input bindings for the direction keys.

In this case, the bindings in the content would override the bindings you've set for the ContentControl itself.

Answer 2

Arrow keys are handled by KeyboardNavigation default. You should disable KeyboardNavigation and make sure control focusable.

  <Grid Background="{Binding Background}" KeyboardNavigation.ControlTabNavigation="None" Focusable="True">
                <Grid.InputBindings>
                    <KeyBinding Key="Left" Command="local:OpsCommands.MoveLeft" />
                    <KeyBinding Key="Up" Command="local:OpsCommands.MoveUp" />
                    <KeyBinding Key="Right" Command="local:OpsCommands.MoveRight" />
                    <KeyBinding Key="Down" Command="local:OpsCommands.MoveDown" />
                </Grid.InputBindings>
            </Grid>

Answer 3

 public ICommand PanRightCmd 
    {
        get { return (ICommand)GetValue(SearchBarEnterCmdProperty); }
        set { SetValue(SearchBarEnterCmdProperty, value); }
    }

...

            PanRightCmd= new RelayCommand(o => PanRightCmdExecute());

https://www.c-sharpcorner.com/UploadFile/20c06b/icommand-and-relaycommand-in-wpf/