C# screen capture

This is achieved by calling windows API functions.
Also see Reference.

using System.Runtime.InteropServices;
using System.Drawing.Imaging;

public class Form1 : System.Windows.Forms.Form {
  #region Dll Imports
    [DllImport("user32.dll")]
    private static extern bool PrintWindow(IntPtr hwnd, IntPtr hdcBlt, uint nFlags);
  #endregion

  private void screen_capture() {
    try {
      Bitmap bm = new Bitmap(this.Width, this.Height);
      Graphics g = Graphics.FromImage(bm);
      IntPtr hdc = g.GetHdc();
      Form1.PrintWindow(this.Handle, hdc, 0);
      //MessageBox.Show("color: " + bm.GetPixel(550, 300));
      g.ReleaseHdc(hdc);
      g.Flush();
      g.Dispose();
      //this.pictureBox1.Image = bm;
      bm.Save("test.bmp");
    } catch (Exception e) {
      MessageBox.Show(this, "error: " + e.Message);
    }
  }

  public Form1() { InitializeComponent(); /* screen_capture(); */  }

  [STAThread]
  static void Main() { Application.Run(new Form1()); }
}