Programming Problems

Okay, I'm trying to create a program to get a sprite moving. I've got a problem. The sprite draws perfectly fine, and I tested keyboard input successfuly by programming it to exit if the X key was pressed. Anyway, the thing is that my sprite draws, but it doesn't respond when I try to move it. It's very frustrating. The sprite is 103 pixels wide and 91 pixels tall. Here's my code. I'm using Microsoft Visual C# and XNA.

Game1.cs

Code:

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 WindowsGame11
{
    /// <summary>
    /// This is the main type for your game
    /// </summary>
    public class Game1 : Microsoft.Xna.Framework.Game
    {
        GraphicsDeviceManager graphics;
        SpriteBatch spriteBatch;      
        Wizard mWizardSprite;

        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            
            mWizardSprite = new Wizard();      
          
            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            
            mWizardSprite.LoadContent(this.Content, "stand2_0");
                      
        }

        /// <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)
        {
            KeyboardState aCurrentKeyboardState = Keyboard.GetState();
          
            // Allows the game to exit
            if (aCurrentKeyboardState.IsKeyDown(Keys.X) == true)
                this.Exit();

            // TODO: Add your update logic here

            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            
            spriteBatch.Begin();
            mWizardSprite.Draw(this.spriteBatch);          
            spriteBatch.End();
            
            base.Draw(gameTime);
        }
    }
}

Wizard.cs

Code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Storage;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.Graphics;


namespace WindowsGame11
{
    class Wizard : Sprite    
    {
        const string WIZARD_ASSETNAME = "stand2_0"; const int START_POSITION_X = 103;
        const int START_POSITION_Y = 91;
        const int WIZARD_SPEED = 160;
        const int MOVE_UP = -1;
        const int MOVE_DOWN = 1;
        const int MOVE_LEFT = -1;
        const int MOVE_RIGHT = 1;

        enum State
        {
            Walking
        }
        State mCurrentState = State.Walking;
        Vector2 mDirection = Vector2.Zero;
        Vector2 mSpeed = Vector2.Zero;
        KeyboardState mPreviousKeyboardState;
    

        public void LoadContent(ContentManager theContentManager)        
        
        {            
            Position = new Vector2(START_POSITION_X, START_POSITION_Y);            
            base.LoadContent(theContentManager, WIZARD_ASSETNAME);        
        }

      
        public void Update(GameTime theGameTime)
        {
            KeyboardState aCurrentKeyboardState = Keyboard.GetState();
            UpdateMovement(aCurrentKeyboardState);
            mPreviousKeyboardState = aCurrentKeyboardState;
            base.Update(theGameTime, mSpeed, mDirection);
        }

        
        private void UpdateMovement(KeyboardState aCurrentKeyboardState)
        {
            if (mCurrentState == State.Walking)
            {
                mSpeed = Vector2.Zero;
                mDirection = Vector2.Zero;
                if (aCurrentKeyboardState.IsKeyDown(Keys.Left) == true)
                {
                    mSpeed.X = WIZARD_SPEED;
                    mDirection.X = MOVE_LEFT;
                }
                else if (aCurrentKeyboardState.IsKeyDown(Keys.Right) == true)
                {
                    mSpeed.X = WIZARD_SPEED;
                    mDirection.X = MOVE_RIGHT;
                }
                if (aCurrentKeyboardState.IsKeyDown(Keys.Up) == true)
                {
                    mSpeed.Y = WIZARD_SPEED;
                    mDirection.Y = MOVE_UP;
                }
                else if (aCurrentKeyboardState.IsKeyDown(Keys.Down) == true)
                {
                    mSpeed.Y = WIZARD_SPEED;
                    mDirection.Y = MOVE_DOWN;
                }

            }

        }

        
        
        
    }
}

Sprite.cs

Code:

using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.Graphics;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace WindowsGame11
{
    class Sprite
    {
        //The asset name for the Sprite's Texture        
        public string AssetName;  
      
        //The Size of the Sprite (with scale applied)        
        public Rectangle Size;    
    
        //The amount to increase/decrease the size of the original sprite.        
        private float mScale = 1.0f;

        //The current position of the Sprite        
        public Vector2 Position = new Vector2(0,0);
            
        //The texture object used when drawing the sprite        
        private Texture2D mSpriteTexture;

        //When the scale is modified through the property, the Size of the        
        //sprite is recalculated with the new scale applied.        
        public float Scale
        {
            get { return mScale; }
            set
            {
                mScale = value;
                //Recalculate the Size of the Sprite with the new scale                
                Size = new Rectangle(0, 0, (int)(mSpriteTexture.Width * Scale), (int)(mSpriteTexture.Height * Scale));
            }
        }

        //Load the texture for the sprite using the Content Pipeline
        public void LoadContent(ContentManager theContentManager, string theAssetName)
        {
            mSpriteTexture = theContentManager.Load<Texture2D>(theAssetName);
            AssetName = theAssetName;
            Size = new Rectangle(0, 0, (int)(mSpriteTexture.Width * Scale), (int)(mSpriteTexture.Height * Scale));
        }

        //Update the Sprite and change its position based on the passed in speed, direction and elapsed time.        
        public void Update(GameTime theGameTime, Vector2 theSpeed, Vector2 theDirection)        
        {            
            Position += theDirection * theSpeed * (float)theGameTime.ElapsedGameTime.TotalSeconds;        
        }

        

        //Draw the sprite to the screen        
        public void Draw(SpriteBatch theSpriteBatch)
        {
            theSpriteBatch.Draw(mSpriteTexture, Position,
                new Rectangle(0, 0, mSpriteTexture.Width, mSpriteTexture.Height),
                Color.White, 0.0f, Vector2.Zero, Scale, SpriteEffects.None, 0);
        }
        
       }
    
}

Can anyone help?