Painting textures to a windows form

Question

I'm trying to get a library I found for using XNA textures on a Windows Form to work. I had it working in a datagridview, but now I'm trying to do the same thing on the windows form itself and I'm running into problems as I'm a novice C# programmer.

Here's what I've got so far:

private void RefreshButton_Click(object sender, EventArgs e)

{

ManageTreeview();

this.Paint += new PaintEventHandler(MainForm_Paint);

this.CreateGraphics();

}

private void MainForm_Paint(object sender,

System.Windows.Forms.PaintEventArgs e)

{

string filePath = Path.Combine(Environment.CurrentDirectory, Path.Combine("Content", Path.Combine("Textures", "racer.dds")));

Image img = XNAGDIImageLoader.LoadImageFromFile(filePath, this.Handle);

e.Graphics.DrawImage(img, new RectangleF(500, 500, img.Width, img.Height) );

}

The refresh button just calls the repainting done in MainForm_Paint. I haven't the foggiest clue however as to how I get my img to paint on the form. The this.CreateGraphics() doesn't seem to be doing anything, and I tried this.Invalidate, but that didn't seem to do anything either.

Mike Gold · Answer

You can't put an Invalidate call inside a Paint Event Handler. This will cause an infinite loop! Let me explain a bit how Windows Painting works. Painting happens in the WM_PAINT event (or Paint event in .NET). You should do all the painting here. Invalidate allows you to force a Window to repaint itself. You don't need to Create a Graphics object to paint it just does it to paint the Windows Form. Just like XNA there is a place to update information and a place to paint. That said invalidation should never happen in the the Paint Event handler or anything the paint event handler calls. Also you might consider putting a try catch block inside your paint event handler so if any of your objects are null that are loading XNA textures the exception will be caught and you can print it to the console (Console.WriteLine(ex.ToString());) Best -Mike

Adam Turner · Answer

Well as a bit of an update I changed things a bit but now I'm crashing Initialize component. private void InitializeComponent() { this .menuStrip1.PerformLayout(); this .Paint += new System.Windows.Forms. PaintEventHandler ( this .MainForm_Paint); this . ResumeLayout( false ); this . PerformLayout(); } Now the other methods look like: private void RefreshButton_Click( object sender EventArgs e) { ManageTreeview(); this .Invalidate(); } protected void MainForm_Paint( object sender System.Windows.Forms. PaintEventArgs e) { Graphics g = e.Graphics; string filePath = Path .Combine( Environment .CurrentDirectory Path .Combine( Content  Path .Combine( Textures  racer.dds ))); Image img = XNAGDIImageLoader .LoadImageFromFile(filePath this .Handle); g.DrawImage(img new System.Drawing. Rectangle (500 500 img.Width img.Height) ); /*String str = 
The time is  + DateTime.Now.ToLongTimeString(); g.DrawString(str Font Brushes.Black 50 75); */ this .Invalidate(); } But now the main form just stalls out and doesn't load the buttons or menustrip. This is really frustrating just to try to paint on a stupid form.