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The statement in Listing 7 , which calls the Update method of the superclass, is always required in the overridden version. Thiscode is placed in the overridden Update method in the skeleton code that is generated by Visual C# (see Listing 1 ) when you create a new Windows Game project.
One of the must useful debugging tools for relatively simple programs is the ability to get information displayed while the program is running. First I willintroduce you to the Microsoft Support website titled How to trace and debug in Visual C# . You will find a great deal of useful information there.
Next [link] I will introduce you to the Debug class, which "Provides a set of methods and properties that help debug your code." There are some very useful tools there also.
Finally, I will show you some examples of using methods from the Debug class.
The Debug class is in the System.Diagnostics namespace. Therefore, you will either need to include that namespace in your"using" list or qualify every reference to the Debug class with the name of the namespace. I chose to include the namespace in my "using" listfor this example.
Listing 8 shows my overridden LoadContent method. Only the code near the end of the method is different from the version of the LoadContent method that I explained in the earlier module titled Xna0118-The XNA Framework and the Game Class .
Listing 8 . Overridden LoadContent method.
protected override void LoadContent() {
//Create a new SpriteBatch, which can be used to// draw textures.
spriteBatch = new SpriteBatch(GraphicsDevice);//Load the image
myTexture = Content.Load<Texture2D>(
"gorightarrow");//Debug code for illustration purposes.
Debug.WriteLine(myTexture.Width);Debug.WriteLine(myTexture.Height);
Debug.WriteLine(Window.ClientBounds.Width);Debug.WriteLine(Window.ClientBounds.Height);
Debug.WriteLine(IsFixedTimeStep);Debug.WriteLine(TargetElapsedTime);
}//end LoadContent The Debug class provides overloaded versions of the WriteLine method, which can be used to display information in the lower-left corner of the Visual C# IDE. These are static methods so they canbe called simply by joining the name of the class to the name of the method as shown in Listing 8 .
I elected to put the code to illustrate this capability in the LoadContent method so that it would execute once and only once. Had I put it in either the Update method or the Draw method, it would have tried to execute during every iteration of the game loopwhich would not be satisfactory.
If you need to display information from inside the game loop, you will probably also need to use a counter with some logic to cause the information tobe displayed only every nth iteration.
The output from each of the six WriteLine statements in Listing 8 (plus some other stuff) is shown in Figure 2 . As you can see, the sprite referred to by myTexture is 143 pixels wide and 107 pixels high. The game window is 800 pixels wide and 480 pixels high. As I mentioned earlier, the value of the IsFixedTimeStep property is True, and the value of the TargetElapsedTime property is 0.0166667 seconds.
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