Screen Toggle

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 Screen_Toggle
{
    /// <summary>
    /// This is the main type for your game
    /// </summary>
    public class ScreenToggle : Microsoft.Xna.Framework.Game
    {

        Color windowColor;
        Color fullScreenColor;
        GraphicsDeviceManager graphics;
        SpriteBatch spriteBatch;

        public ScreenToggle()
        {
            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
            windowColor = new Color(255, 0, 0);
            fullScreenColor = new Color(0, 255, 0);

            graphics.PreferredBackBufferWidth = 1920;
            graphics.PreferredBackBufferHeight = 1080;
            graphics.IsFullScreen = true;
            graphics.ApplyChanges();
            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 here
            if (Keyboard.GetState().IsKeyDown(Keys.Space))
            {
                if (graphics.IsFullScreen)
                {
                    graphics.PreferredBackBufferWidth = 300;
                    graphics.PreferredBackBufferHeight = 300;
                    graphics.IsFullScreen = false;
                    graphics.ApplyChanges();
                }
            }
            base.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 here
            if (graphics.IsFullScreen)
                GraphicsDevice.Clear(fullScreenColor);
            else
                GraphicsDevice.Clear(windowColor);
            base.Draw(gameTime);
        }
    }
}