WinForms and MVC

May 26, 2010 MVC, WinForms

I recently became interested in doing MVC inside of a Windows Forms app. I found a few MVC frameworks which work with WinForms (see here) but they didn't really interest me. Too heavy I felt for what I was looking to do. I ended up with a solution looking something like this:

There is really only one controller and that is the "Application" class. It contains all the methods your app can call to manipulate your models, which are in the "Data" folder / namespace. The "WinFormsApplication" class inherits from the "Application" class and just sets the view to an instance of "WinFormsView". The "Application" class communicates with the view through the "IView" interface. The "WinFormsView" class is a Windows Forms implementation of that view. The "Application" class and your models are not coupled in any way to your Windows Forms implementation of the view.

If you want you view to be as dumb as possible, your view can communicate with the "Application" class only through events. In my case though, I choose to go with a smart view and have the view call back to methods in the "Application" class. The "Application" class tells the view when models are loaded and unloaded. The view subscribes to events on the models and reacts to the events.

All of my forms and controls communicate with each other through the "WinFormsView" class. One control might change the value of a property in the "WinFormsView" class and another control might subscribe to a change event and update as necessary. This keeps the controls and forms slightly less coupled.

It's not a perfect implementation of MVC but it keeps my model logic decoupled enough from my view logic that I can later implement a WPF version of the view I think.

Drawing Rectangles with SpriteBatch

March 29, 2010 C#, Code Snippets, Xna

Just a quick code snippet which adds an extension method for drawing Rectangles to SpriteBatch:

public static class SpriteBatchHelper { static Texture2D pixel; private static void LoadPixel(GraphicsDevice graphicsDevice) { if(pixel == null) { pixel = new Texture2D(graphicsDevice, 1, 1); pixel.SetData<Color>(new Color[] { Color.White }); } } public static void DrawRectangle(this SpriteBatch spriteBatch, Rectangle rectangle, Color color) { LoadPixel(spriteBatch.GraphicsDevice); spriteBatch.Draw(pixel, rectangle, color); } }

C# Extension Methods in your own Library

March 08, 2010 C#, Extension Methods

Normally I use extension methods in C# to extend a library that I did not write and therefore I have no control over. There are situations where it makes sense to use extension methods for a library that you yourself are writing.

For example, when you have interfaces in your library. You want to keep the number of methods in that interface as low as possible so that classes implementing the interface don't have to do a lot of heavy lifting. This means cutting out methods in an interface that are for the most part just syntactic sugar for another method in the interface.

public interface IServiceContainer { void AddService(Type type, Object provider); object GetService(Type type); } public static class IServiceContainerExtensions { public static void AddService<T>(this IServiceContainer services, object provider) { services.AddService(typeof(T), provider); } public static T GetService<T>(this IServiceContainer services) where T : class { return services.GetService(typeof(T)) as T; } public static T GetRequiredService<T>(this IServiceContainer services) where T : class { T service = services.GetService(typeof(T)) as T; if(service == null) throw new ServiceNotFoundException(typeof(T)); return service; } }

All of the methods in IServiceContainerExtensions are just helper methods for method in IServiceContainer. By making them extension methods in our own library though, we've made the barrier to entry lower. Other people can implement the interface and in a sense "inherit" the helper methods as well.

Creating and consuming services in your XNA Game

February 18, 2010

The GameServiceContainer implements the IServiceProvider interface and the MSDN documentation says about the IServiceProvider interface:

Defines a mechanism for retrieving a service object; that is, an object that provides custom support to other objects.

This article will "attempt" to describe how can you use the GameServiceContainer in your XNA game, in both your GameComponent(s) and your game's entity objects.

Read More

Changing the PlatformTarget in Visual C# Express

January 18, 2010 MSBuild

Some project types in Visual C# Express (Empty Project) will not allow you to change the PlatformTarget from the UI. You can still change the target platform though by editing the .csproj file in a text editor. Close the project and open it up in your favorite text editor (I use Notpad++). The .csproj file is really just a XML file. You should see somewhere in the file something like:

<PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
		....
	</PropertyGroup>
	<PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
		....
	</PropertyGroup>

Inside the PropertyGroup elements, add the PlatformTarget element:

<PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
		....
		<PlatformTarget>x86</PlatformTarget>
	</PropertyGroup>
	<PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
		....
		<PlatformTarget>x86</PlatformTarget>
	</PropertyGroup>

Save the file and open your project back up. Your project's output should now target only x86.