Using Keyboard Input in WPF - Page 1
       by kirupa  |  7 March 2007

In my earlier tutorial, I talked about event handlers and how to use them. I did not go into great detail, because in many cases, your Integrated Development Environment (IDE) such as Visual Studio takes care of both binding an event to an event handler as well as creating the event handler if necessary. In most cases, the code the IDE provides for you is all you really need to detect the events. But...there are times when you need to go beyond what the IDE provides and write some code yourself.

In this article, I will focus on dealing with keyboard input. Your IDE will easily allow you to have an event handler bound to a keyboard-related event, but beyond that, though, you are on your own. That is where this tutorial comes in. I will first explain how to detect individual keys and then move on to the fun topic of how to handle key combinations such as Alt + F4, Ctrl + S, etc.

Download Source
So, before we continue, you should download KeyboardEvents.zip for this tutorial, extract the files to your hard drive, and open the project up in Visual Studio. Don't worry - the interesting stuff hasn't been filled in. You'll do that yourself with help from this tutorial, for only the code unrelated to using keyboard input have already been written for you.

Becoming Familiar with the Program
After you have downloaded and extracted (unzipped) the files from KeyboardEvents.zip to a location on your hard drive, open the KeyboardEvents solution in Visual Studio. When you open the Window1.xaml.cs file, you should see the following code:

namespace KeyboardEvents

{

public partial class Window1

{

public Window1()

{

this.InitializeComponent();

 

// Insert code required on object creation below this point.

}

 

private void KeyUpEventHandler(object sender, KeyEventArgs e)

{

 

}

 

private void KeyDownEventHandler(object sender, KeyEventArgs e)

{

 

}

}

}

If you press F5 to run your application, you should then see the following:

[ what your application looks like ]

Your application is nothing more than a window with a textbox. When you type something in your textbox, though, the two event handlers in your code get fired because your XAML definition maps the KeyDown and KeyUp events to the KeyUpEventHandler and KeyDownEventHandler event handlers in the code-behind file Window1.xaml.cs:

<TextBox Margin="8,8,8,8" x:Name="txtMain" AcceptsReturn="True" AcceptsTab="True" Text="" TextWrapping="Wrap" KeyDown="KeyDownEventHanlder" KeyUp="KeyUpEventHanlder" VerticalScrollBarVisibility="Auto"/>

By now, you should have a good idea of what event handlers (see Event Handler tutorial), so I will not focus too much on the files you downloaded. Instead, this tutorial will help you write some code in your event handlers to learn how to deal with keyboard input.

Over the next few pages, I will provide some code and explain how to perform common actions that you would normally want to do when writing an application that depends heavily on keyboard input.

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