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First, i'm not too good known to programming (17 and still learning it), so sorry if my code isn't that good ^^

I've seen something about 2D Engine in C#, and that they're actually not that hard to code, so i wanted to give it a shot, but now i've got a problem:

I created a Panel in the Form, and then it's getting painted I "extract" the Graphics Object, and give it to my "Engine"

    private void panel1_Paint(object sender, PaintEventArgs e)
    {
        Console.WriteLine("Draw");
        graphics.setG(e.Graphics);
    }

The Engine just "saves" the Graphics object

    public void setG(Graphics g)
    {
        this.g = g;
    }

Now i've got the usual Game Loop, executing an Update and a Draw method every 1/60 Seconds, part of the draw Method:

        for(int i = 0;i < images.Count; i++)
        {
            var curr = images[i];
            g.DrawImage(curr.img, (int)Math.Round(curr.x), (int)Math.Round(curr.y));
        }

Where of course img is an Image, x and y are floats, casted to ints, now i get "unhandled exception of type 'System.ArgumentException' occured in System.Drawing.dll" in the Line

            g.DrawImage(curr.img, (int)Math.Round(curr.x), (int)Math.Round(curr.y));

Exception Detail (Tried to translate a few words, original log is german):

System.ArgumentException was unhandled
  HResult=-2147024809
  Message=Invalid Parameter.
  Source=System.Drawing
  StackTrace:
       at System.Drawing.Graphics.CheckErrorStatus(Int32 status)
       at System.Drawing.Graphics.DrawImage(Image image, Int32 x, Int32 y)
       at _2D_Engine.GraphicsEngine.Draw(Graphics g) in C:\Users\Paul\Documents\Visual Studio 2015\Projects\2D Engine\2D Engine\GraphicsEngine.cs:Line 38.
       at _2D_Engine.Form1.gameLoop() in C:\Users\Paul\Documents\Visual Studio 2015\Projects\2D Engine\2D Engine\Form1.cs:Line 54.
       at _2D_Engine.Form1.gameLoop() in C:\Users\Paul\Documents\Visual Studio 2015\Projects\2D Engine\2D Engine\Form1.cs:Line 58.
       at _2D_Engine.Form1.gameLoop() in C:\Users\Paul\Documents\Visual Studio 2015\Projects\2D Engine\2D Engine\Form1.cs:Line 58.
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()

This happens whatever i'm trying to draw to the Panel, also when I try to draw a Polygon for example, i get the same Exception. Not sure if I misunderstood anything about how to write the Game Loop, because it doesn't happen when i just call the draw Method from the Paint method, but the Paint Method isn't called everytime I want an object to move, so I can't use only it for the Draw Loop, i'm pretty puzzled right now ^^

c# loops drawing draw
  |
  this question asked Mar 4 '16 at 17:24 Potheker 16 1      Do not store and use PaintEventArgs.Graphics outside of the Paint event. Actually do all the painting only in that event. Use Invalidate method when you want to repaint (when you want object to move etc.) –  Ivan Stoev Mar 4 '16 at 17:42      @IvanStoev ok, i've seen a tutorial where the draw-method was called in the game-loop, but whatever... it works when i just call this.Invalidate(); in my game-loop, well kind of... it just repaints when i "use" the window, when i take it and move it on the screen for example, when it stands still, nothing happens, what did i do wrong? ^^ –  Potheker Mar 4 '16 at 18:10

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