Question

Whenever I call the method Draw in Sprite, it won’t draw it because X, Y, Width and Height are 0. 🙁

code:

class Sprite   
{
    protected int Y;// { get; set; }
    protected int X;// { get; set; } { get; set; }
    protected int Width;// { get; set; } { get; set; }
    public int Height;// { get; set; } { get; set; }
    protected Image image;// { get; set; } { get; set; }

    public Sprite()
    {

    }

    public void Draw(Graphics drawArea)
    {
        Image sImage = Image.FromFile("alien.jpg");
        drawArea.Clear(Color.White);
        drawArea.DrawImage(sImage, X, Y, Width, Height);
    }
}

class User:Sprite
{
    public User()
    {

    }

    public User(int width, int height, int userWidth, int userHeight)
    {
        Sprite sprite = new Sprite();
        Image UserImage = Image.FromFile("alien.jpg");

        X = width;
        Y = height;
        Width = userWidth;  
        Height = userHeight;
        image = UserImage;
    }
}

ps: sprite.Draw is declared in another method in another class, but that all should work just fine.
Thanks for helping and probably saving me hours of time 🙂

Nick

EDIT

here is the subclass which gives the parameter and other stuff.

  Alien mAlien;
User mUser;
protected int mLevel;


public gameLogic()
{


}


public gameLogic(int width, int height, int level)
{
  mUser = new User(width / 2, height - 30, 30, 30);
  mAlien = new Alien(width / 2, 5, 30, 30, "alien.jpg", 10 * level);
  mLevel = level;
}

public void drawAll(Graphics drawArea)
{
  Sprite sprite = new Sprite();
  sprite.Draw(drawArea);
}

Im sorry for all these errors that’ll probably occur, Im a new student 🙂

Answer 1

Try this:

public User(int width, int height, int userWidth, int userHeight)
{
    Sprite sprite = new Sprite();
    Image UserImage = Image.FromFile("alien.jpg");

    sprite.X = width;
    sprite.Y = height;
    sprite.Width = userWidth;  
    sprite.Height = userHeight;
    sprite.image = UserImage;
}

In order to access the fields of the sprite, you have to specify which Sprite object you are modifying. This is done by writing the name of the variable followed by .

EDIT: Just realized that there is another problem – your User class is inheriting from the Sprite class. Apparently your users are sprites, according to the comments, so you’ll want to never instantiate a Sprite, and just use the User class instead:

class User:Sprite
{
    public User(int width, int height, int userWidth, int userHeight)
    {
        Image UserImage = Image.FromFile("alien.jpg");

        X = width;
        Y = height;
        Width = userWidth;  
        Height = userHeight;
        image = UserImage;
    }
}

Then instead of calling draw on a sprite in the other file, use the following:

User user = new User(x, y, width, height)

...

user.draw();

The key here is to make sure you are using new User... and not new Sprite – even if you are assigning to a Sprite variable e.g. Sprite s = new User(...);.

Then just make sure you call draw on the same object – the user.draw line. If you want to check that you’re doing it right, try making Sprite abstract – abstract class Sprite – that way there will be compile errors if you try to instantiate Sprite instead of User.

EDIT 2: Ok, all you really need to do is change your calling code:

public void drawAll(Graphics drawArea)
{
    mUser.draw(drawArea);
    mAlien.draw(drawArea);
}