使用Visual C#重绘标题栏

在做拖动小窗口程序时，遇到一个问题，怎么样对标题栏进行绘制，弄了半天才弄出来。和VC中原理差不多，但在.net下需要将API中的HDC通过Graphics.FromHdc()转换为System.Drawing.Graphics

 

  　　 程序运行结果如下：

　　

 

 

   代码如下：

/// <summary>
        /// 对窗口的标题栏进行重绘和设置
        /// </summary>
        /// <param name="hwnd"></param>
        /// <returns></returns>
        [DllImport("User32.dll")]
        private static extern IntPtr GetWindowDC(IntPtr hwnd);
        [DllImport("User32.dll")]
        private static extern int ReleaseDC(IntPtr hwnd,IntPtr hdc);
        [DllImport("Kernel32.dll")]
        private static extern int GetLastError();
        //标题栏按钮的矩形区域
        Rectangle m_rect = new Rectangle(3,4,194,18);

        protected override void WndProc(ref Message m)
        {
            base.WndProc(ref m);

            switch (m.Msg)
            {
                case 0x86://WM_NCACTIVATE
                    goto case 0x85;
                case 0x85://WM_NCPAINT
                    {
                        //处理OnPaint事件
                        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);
                        gs.FillRectangle(new LinearGradientBrush(m_rect, Color.Green, Color.Green, LinearGradientMode.BackwardDiagonal), m_rect);

                        StringFormat strFmt = new StringFormat();
                        strFmt.Alignment = StringAlignment.Center;
                        strFmt.LineAlignment = StringAlignment.Center;
                        gs.DrawString("标题栏重绘例子", this.Font, Brushes.BlanchedAlmond, m_rect, strFmt);
                        gs.Dispose();

                        //释放GDI资源
                        ReleaseDC(m.HWnd, hDC);
                        break;
                    }
                case 0xA1://WM_NCLBUTTONDOWN
                    {
                        //处理MouseDown事件
                        Point mousePoint = new Point((int)m.LParam);
                        mousePoint.Offset(-this.Left, -this.Top);
                        if (m_rect.Contains(mousePoint))
                        {
                            MessageBox.Show("这是一个对标题栏进行重绘的例子！");
                        }
                        break;
                    }
                case 0x00A0://WM_NCMOUSEMOVE
                    {
                        //处理MouseMove事件
                        Point mousePoint = new Point((int)m.LParam);
                        mousePoint.Offset(-this.Left, -this.Top);
                        if (m_rect.Contains(mousePoint))
                        {
                            Cursor.Current = Cursors.SizeAll;
                        }
                        break;
                    }
            }
        }


        主要事件参照表：

winuser.h中，定义如下：
#define WM_NCMOUSEMOVE                  0x00A0
#define WM_NCLBUTTONDOWN                0x00A1
#define WM_NCLBUTTONUP                  0x00A2
#define WM_NCLBUTTONDBLCLK              0x00A3
#define WM_NCRBUTTONDOWN                0x00A4
#define WM_NCRBUTTONUP                  0x00A5
#define WM_NCRBUTTONDBLCLK              0x00A6
#define WM_NCMBUTTONDOWN                0x00A7
#define WM_NCMBUTTONUP                  0x00A8
#define WM_NCMBUTTONDBLCLK              0x00A9

 

完毕。^_^