c#在WinForm中重写ProgressBar控件（带%的显示）

c#在WinForm中重写ProgressBar控件（带%的显示）

2009-05-14 13:13

    #region 定义textProgressBar控件的类
    namespace csPublish
    {
        [ToolboxItem(true)]
        class textProgressBar : System.Windows.Forms.ProgressBar
        {
            [System.Runtime.InteropServices.DllImport("user32.dll ")]
            static extern IntPtr GetWindowDC(IntPtr hWnd);
            [System.Runtime.InteropServices.DllImport("user32.dll ")]
            static extern int ReleaseDC(IntPtr hWnd, IntPtr hDC);

            private System.Drawing.Color _TextColor = System.Drawing.Color.Black;
            private System.Drawing.Font _TextFont = new System.Drawing.Font("SimSun ", 12);

            public System.Drawing.Color TextColor
            {
                get { return _TextColor; }
                set { _TextColor = value; this.Invalidate(); }
            }

            public System.Drawing.Font TextFont
            {
                get { return _TextFont; }
                set { _TextFont = value; this.Invalidate(); }
            }

            protected override void WndProc(ref   Message m)
            {
                base.WndProc(ref   m);
                if (m.Msg == 0xf || m.Msg == 0x133)
                {
                    //拦截系统消息，获得当前控件进程以便重绘。  
                    //一些控件（如TextBox、Button等）是由系统进程绘制，重载OnPaint方法将不起作用.  
                    //所有这里并没有使用重载OnPaint方法绘制TextBox边框。  
                    //  
                    //MSDN:重写   OnPaint   将禁止修改所有控件的外观。  
                    //那些由   Windows   完成其所有绘图的控件（例如   Textbox）从不调用它们的   OnPaint   方法，  
                    //因此将永远不会使用自定义代码。请参见您要修改的特定控件的文档，  
                    //查看   OnPaint   方法是否可用。如果某个控件未将   OnPaint   作为成员方法列出，  
                    //则您无法通过重写此方法改变其外观。  
                    //  
                    //MSDN:要了解可用的   Message.Msg、Message.LParam   和   Message.WParam   值，  
                    //请参考位于   MSDN   Library   中的   Platform   SDK   文档参考。可在   Platform   SDK（“Core   SDK”一节）  
                    //下载中包含的   windows.h   头文件中找到实际常数值，该文件也可在   MSDN   上找到。  
                    IntPtr hDC = GetWindowDC(m.HWnd);
                    if (hDC.ToInt32() == 0)
                    {
                        return;
                    }

                    //base.OnPaint(e);
                    System.Drawing.Graphics g = Graphics.FromHdc(hDC);
                    SolidBrush brush = new SolidBrush(_TextColor);
                    string s = string.Format("{0}%", this.Value * 100 / this.Maximum);
                    SizeF size = g.MeasureString(s, _TextFont);
                    float x = (this.Width - size.Width) / 2;
                    float y = (this.Height - size.Height) / 2;
                    g.DrawString(s, _TextFont, brush, x, y);
                    //返回结果  
                    m.Result = IntPtr.Zero;
                    //释放  
                    ReleaseDC(m.HWnd, hDC);
                }
            }
        }
    }
    #endregion