[转载]C#重绘标题栏

using System.Runtime.InteropServices;

public partial class frmMain : Form  
{
    [DllImport("User32.dll")]  
    private static extern IntPtr GetWindowDC(IntPtr hwnd);
    [DllImport("User32.dll")]  
    private static extern int ReleaseDC(IntPtr hwnd, IntPtr hdc);

    protected override void WndProc(ref Message m)  
    {
        base.WndProc(ref m);
        switch (m.Msg)  
        {
            case 0x84:  
                //这里是鼠标的移动事件  
                break;
            case 0x86: //WM_NCACTIVATE  
                goto case 0x85;
            case 0x85: //WM_NCPAINT  
                //CaptionButtonSize获取窗口标题栏中的按钮的标准大小（以像素为单位）。  
                Size si = new Size(SystemInformation.CaptionButtonSize.Width, SystemInformation.CaptionButtonSize.Height);
                IntPtr hDC = GetWindowDC(m.HWnd);
                //把DC转换为.NET的Graphics就可以很方便地使用Framework提供的绘图功能了  
                Graphics gs = Graphics.FromHdc(hDC);
                Image img = Image.FromFile(Application.ExecutablePath.Replace(".EXE", ".png"));
                //显示背景图片  
                gs.DrawImage(img, 0, 0);
                gs.Dispose();
                //释放GDI资源  
                ReleaseDC(m.HWnd, hDC);
                break;
            case 0xA1://WM_NCLBUTTONDOWN  
                break;
        }
    }
}