DirectX DirectInput In C#

Introduction

This wiki page discusses the method of implementing DirectInput features using DirectX 9 and C#.

Devices

In DirectX every piece of hardware or software emulated hardware is considered a device. We use devices to set up our game window, we use devices to set up our keyboard, mouse and joysticks. So to begin to access the keyboard we first need to include the DirectInput namespace.

using Microsoft.DirectX.DirectInput;

Next we need to create a device. Now ideally we would wrap the device in either an interface or an abstract class. We also want to be able to capture events in that class. Let's use an abstract class, because we can define some of the code and allow the implementor to define the rest.

namespace Uniprogamer.Common.IO
{
	public abstract class !DirectInputKeyboardDevice
	{
		protected static Device _keyboard;
		protected static Guid _keyboardGuid;

		protected !DirectInputKeyboardDevice()
		{
			!KeyboardGuid = !SystemGuid.Keyboard;
			Keyboard = new Device(_keyboardGuid);
		}

		protected !DirectInputKeyboardDevice(Guid keyboardGuid)
		{
			!KeyboardGuid = keyboardGuid;
			Keyboard = new Device(keyboardGuid);
		}

		public Device Keyboard
		{
			get { return _keyboard; }
			set { _keyboard = value; }
		}

		public Guid !KeyboardGuid
		{
			get { return _keyboardGuid; }
			set
			{ 
				_keyboardGuid = value;
				Keyboard = new Device(_keyboardGuid);
			}
		}
	}
}

As you can see I have two protected constructors that I want the user to use. Granted the user of this abstract class may also write other constructors to their liking. I chose these two, a default constructor that uses the system guid for the keyboard device, and a second one that allows the developer to set the guid of the keyboard manually. System.Keyboard will return whatever .NET found to be the correct guid for the attached keyboard. You should also notice that I created two fields and properties to access them. Both fields are static, because I'm assuming that there will only ever be one keyboard attached to the computer at any given time, so I don't want there to ever be more than one keyboard device or one keyboard device guid. Again you should also notice that I use the properties to access the static fields inside of the methods and constructors. This is a completely standard way of accessing static fields in C#. Now to add some configuration pieces.

The main configuration pieces you'll need to take care of in some way or another are teh Cooperative Level, Data Format, and possibly the Event Notification setting. Some things you may want to expose through properties might include properties of the _keyboard device. You should also expose the events that the _keyboard device can send.

If you have any questions, feel free to ask me.

Nathan Lane
Uniprogamer Team