The using directive
You learned earlier that one of the benefits of the using directive is to eliminate the requirement to always type the namespace (such as System ) when referring to a class that belongs to that namespace. That is the purpose of the using directive at the top of Listing 2 .
However, there is another benefit that derives from the using directive that may be more important.
Memory management
One of the big issues in game programming (or any kind of programming that makes use of graphics files, sound files, or other large resource files) is tomake certain that the memory occupied by those resources is freed up as soon as the resource is no longer needed.
Without going into a lot of detail, the use of the using keyword inside the Main method in Listing 2 will assure that the Dispose method is called to free up all of the memory occupied by the Game1 object when control reaches the closing curly brace following the using keyword.
Don't modify the file named Program.cs
As an XNA game programmer, you shouldn't normally have any reason to modify the contents of the file named Program.cs . We need to leave it alone and modify the file named Game1.cs instead.
The Game1 class
I told you earlier that when you create a new Windows Game project, the file named Game1.cs is opened in the editor pane. Listing 3 shows the contents of that file.
Listing 3 . Initial contents of the file named Game1.cs.
using System;
using System.Collections.Generic;using System.Linq;
using Microsoft.Xna.Framework;using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;using Microsoft.Xna.Framework.GamerServices;
using Microsoft.Xna.Framework.Graphics;using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Media;namespace WindowsGame2
{///<summary>/// This is the main type for your game
///</summary>public class Game1 : Microsoft.Xna.Framework.Game
{GraphicsDeviceManager graphics;
SpriteBatch spriteBatch;public Game1()
{graphics = new GraphicsDeviceManager(this);
Content.RootDirectory = "Content";}
///<summary>/// Allows the game to perform any initialization/// it needs to before starting to run.
/// This is where it can query for any required/// services and load any non-graphic
/// related content. Calling base.Initialize/// will enumerate through any components
/// and initialize them as well.///</summary>protected override void Initialize()
{// TODO: Add your initialization logic here
base.Initialize();}
///<summary>/// LoadContent will be called once per game and is the place to load
/// all of your content.///</summary>protected override void LoadContent()
{// Create a new SpriteBatch, which can be used to draw textures.
spriteBatch = new SpriteBatch(GraphicsDevice);// TODO: use this.Content to load your game content here
}///<summary>/// UnloadContent will be called once per game and is the place to unload
/// all content.///</summary>protected override void UnloadContent()
{// TODO: Unload any non ContentManager content here
}///<summary>/// Allows the game to run logic such as updating the world,
/// checking for collisions, gathering input, and playing audio.///</summary>///<param name="gameTime">Provides a snapshot of timing values.</param>protected override void Update(GameTime gameTime)
{// Allows the game to exit
if(GamePad.GetState(PlayerIndex.One).Buttons.Back==ButtonState.Pressed)this.Exit();
// TODO: Add your update logic herebase.Update(gameTime);
}///<summary>/// This is called when the game should draw itself.
///</summary>///<param name="gameTime">Provides a snapshot of timing values.</param>protected override void Draw(GameTime gameTime)
{GraphicsDevice.Clear(Color.CornflowerBlue);
// TODO: Add your drawing code herebase.Draw(gameTime);
}}
}