WPF: How To Use Command & Input Bindings [closed]

Question

Command & Input Bindings seem to be extremely complicated in WPF - binding specific commands to certain inputs don't always seem to work. How should I go about doing this?

--Self Answered--

I've updated with a personal answer with my own findings considering how long it's taken me to find information, understand, and actually implement these convoluted things.

Bindings in WPF seem to be an unfriendly concept, especially if you have no experience. Hopefully this makes people's lives easier.

Answer 1

First, add the application namespace at the top of xaml file that will use the binding: ex.

xmlns:main="clr-namespace:MyApplication"

Next, add a custom static class to contain the commands, outside the main window class: ex.

public static class Command {     public static RoutedCommand GSToggleCmd = new RoutedCommand();     public static RoutedCommand ScreenZoomCmd = new RoutedCommand(); } 

My main window class happened to be 'MainWindow'; I defined the Command class right below it.

Finally, add the command bindings in the xaml file

<Window.CommandBindings>     <CommandBinding Command="main:Command.GSToggleCmd" Executed="GameStateToggleExecuted" />     <CommandBinding Command="main:Command.ScreenZoomCmd" Executed="ApplyScreenFitCmd" /> </Window.CommandBindings> 

Command="" refers to the RoutedCommand that you'll be binding to. I've named my namespace reference main, hence the syntax main:Command.nameofcommand

Executed="" refers to the function called when the command is triggered.

Example of Executed function:

private void ApplyScreenFitCmd( object sender, ExecutedRoutedEventArgs args ) {     string proportionStr = args.Parameter as string; } 

And that's it. A minimalistic, simple approach to using CommandBindings in WPF.

To add a command, just chuck in a new static RoutedCommand in the Command class and add the CommandBinding in the xaml file under Window.CommandBindings

Note:

Visual Studio's Xaml editor may complain at first that some command cannot be found. Building the project will resolve the issue.

Further Information:

You can also trigger CommandBindings through InputBindings. (key triggers)

Example (placed in the Xaml file that will use them):

<Window.InputBindings>     <KeyBinding Key="F5" Command="main:Command.GSToggleCmd" />     <KeyBinding Modifiers="Shift+Alt" Key="Q" Command="main:Command.ScreenZoomCmd" CommandParameter="1.0" />     <KeyBinding Modifiers="Alt" Key="W" Command="main:Command.ScreenZoomCmd" CommandParameter="0.75" />     <KeyBinding Modifiers="Alt" Key="E" Command="main:Command.ScreenZoomCmd" CommandParameter="0.5" /> </Window.InputBindings> 

So it's basically the Key press triggers KeyBinding, which in turn triggers the CommandBinding of the command specified, triggering the corresponding call function.

As with the above example, you can also define CommandParameter to send in a parameter to the function finally called. The nice thing about this is that, like the above, you can reuse the same CommandBinding by just chucking in different CommandParameters.

You can also trigger CommandBindings through Buttons, MenuItems, etc.

Example:

<MenuItem Header="100%" InputGestureText="Alt+Q" Command="main:Command.ScreenZoomCmd" CommandParameter="1.0"/> 

This is the same syntax as with the InputBindings.

It took me a while before I settled down on a minimalistic, uniform way to use bindings in WPF. I hope this article prevents all the struggle that this concept seems to easily cause.