Change generic queue Queue<T> class to non-generic Queue class

Hey guys. I have this code here fully working.....Its currently using using System.Collections.Generic;

but i want to change it to use a non generic queue class I'm having alot of trouble grasping the concept ..any help and direction will be greatly appreciated! my attempt from online examples:

//edited code here

    Queue Letters = new Queue(); //new code
    FallingCharacter myFallingCharacter = new FallingCharacter();//new code
    Letters.Enqueue(myFallingCharacter); //new code

    //Queue<FallingCharacter> Letters = new Queue<FallingCharacter>();

The original code is:

partial class Game1 : Microsoft.Xna.Framework.Game
{

    public enum GameState
    {
        StateMainMenu,
        StatePlaying,
        StateGameOver,
        StateHelp,
    }


    GameState currentState = GameState.StateMainMenu;

    KeyboardState kbState;
    Keys[] pressedKeys;


    Queue<FallingCharacter> Letters = new Queue<FallingCharacter>();

    float nextLetterTime = 0.6f;
    int NextSpeedup = 20; // in 20 points lets speed it up
    int iSpeed = 2;

    int Score = 0;

    GraphicsDeviceManager graphics;
    SpriteBatch spriteBatch;
    SpriteFont spriteFont;
    public Game1()
    {
        graphics = new GraphicsDeviceManager(this);
        Content.RootDirectory = "Content";

        graphics.PreferredBackBuffer开发者_Go百科Width = 800;
        graphics.PreferredBackBufferHeight = 600;
        graphics.ApplyChanges();
    }


    protected override void LoadContent()
    {
        spriteBatch = new SpriteBatch(GraphicsDevice);
        spriteFont = Content.Load<SpriteFont>("GameFont");

        base.LoadContent();
    }


    public void OnKeyPressed(Keys k)
    {

        if ((currentState == GameState.StateMainMenu ||
            currentState == GameState.StateGameOver)
            && k == Keys.Enter)
        {
            currentState = GameState.StatePlaying;

            nextLetterTime = 0.0f;
            NextSpeedup = 20; // in 20 points lsets speed it up
            iSpeed = 1;
            Score = 0;
        }
        else if (currentState == GameState.StatePlaying)
        {
            string sName = Enum.GetName(typeof(Keys), k);
            if (Letters.Count > 0 &&
                    String.Compare(Letters.Peek().character.ToString(), sName) == 0)
            {
                Score += 100;
                Letters.Dequeue();

                NextSpeedup--;

                if (NextSpeedup <= 0)
                {
                    iSpeed++;

                    NextSpeedup = 20;
                }
            }
        }

        if (k == Keys.Escape)
        {
            this.Exit();
        }
    }


    protected override void Update(GameTime gameTime)
    {
        // The time since Update was called last
        float elapsed = (float)gameTime.ElapsedGameTime.TotalSeconds;


        kbState = Keyboard.GetState();

        Keys[] newKeys = (Keys[])kbState.GetPressedKeys().Clone();

        if (pressedKeys != null)
        {
            foreach (Keys k in newKeys)
            {
                bool bFound = false;

                foreach (Keys k2 in pressedKeys)
                {
                    if (k == k2)
                    {
                        bFound = true;
                        break;
                    }
                }

                if (!bFound)
                {
                    OnKeyPressed(k);
                }
            }
        }

        pressedKeys = newKeys;

        if (currentState == GameState.StatePlaying)
        {

            foreach (FallingCharacter fc in Letters)
            {
                if (fc.Pos.Y + 50 > graphics.PreferredBackBufferHeight)
                {
                    currentState = GameState.StateGameOver;

                    Letters.Clear();
                    break;
                }
                else
                {
                    fc.Pos.Y += (elapsed * (float)(iSpeed * 40));
                }
            }


            nextLetterTime -= elapsed;

            if (nextLetterTime <= 0 && currentState != GameState.StateGameOver)
            {
                nextLetterTime = 0.75f - (iSpeed * .03f);
                Random r = new Random();

                Letters.Enqueue(new FallingCharacter(
                    r.Next(graphics.PreferredBackBufferWidth - 30), -30,
                    Color.LightGreen, (char)((int)'A' + r.Next(25))));

            }
        }

        base.Update(gameTime);
    }

    protected override void Draw(GameTime gameTime)
    {
        GraphicsDevice.Clear(Color.CornflowerBlue);

        spriteBatch.Begin(SpriteSortMode.Immediate, BlendState.AlphaBlend); 

        switch (currentState)
        {
            case GameState.StateMainMenu:
                {
                    spriteBatch.DrawString(spriteFont,
                        "Press Enter to begin", 
                        new Vector2(graphics.PreferredBackBufferWidth / 4,
                        graphics.PreferredBackBufferHeight / 2), 
                        Color.White);
                }
                break;
            case GameState.StatePlaying:
                {
                    spriteBatch.DrawString(spriteFont, 
                        "Score: " + Score.ToString(), 
                        new Vector2(10, 10), Color.White);

                    foreach (FallingCharacter fc in Letters)
                    {
                        fc.Render(spriteBatch, spriteFont);
                    }
                }
                break;
            case GameState.StateGameOver:
                {
                    spriteBatch.DrawString(spriteFont, 
                        "Score: " + Score.ToString(), 
                        new Vector2(10, 10), Color.White);
                    spriteBatch.DrawString(spriteFont, 
                        "Game Over", 
                        new Vector2(graphics.PreferredBackBufferWidth / 3, 
                                    graphics.PreferredBackBufferHeight / 2),
                        Color.LightBlue);
                    spriteBatch.DrawString(spriteFont, 
                        "Press Return to Continue", 
                        new Vector2(graphics.PreferredBackBufferWidth / 6, 
                            graphics.PreferredBackBufferHeight / 2 + 50), 
                        Color.LightBlue);
                }
                break;
        }

        spriteBatch.End();

        base.Draw(gameTime);
    }

}
}

---

All you need to do when using a non-generic collection is to cast the returned objects to FallingCharacter before you use them. Otherwise, it should be pretty much the same, with Enqueue, Dequeue, Peek, etc.

E.g.:

String.Compare( ( Letters.Peek() as FallingCharacter ).character.ToString(), sName )

The foreach's can stay the same, because they'll do the typecasting implicitly as long as you specify FallingCharacter as the type.

If you want to be extra safe, add some type checking before blindly assuming the object is a FallingCharacter.