给窗体中控件绘图的几种方法

方法一：WINDOWS API画法

1. //获取要绘制的控件句柄
   
2. Image img = GetWindow(this.tabPage12.Handle);
   
3. //在母容器上创建图形对象 
   
4. Graphics gOut = mOut.pnlOut.CreateGraphics();
   
5. //在指定位置按指定大小绘出image 
   
6. gOut.DrawImage((Image)img, form1.pnlImage.DisplayRectangle, this.tabPage12.DisplayRectangle, GraphicsUnit.Pixel);
   
7. //释放图形对象所有资源 
   
8. gOut.Dispose(); 
   
9. img.Dispose(); 
   
10. GC.Collect(); 
    
11. form1.pnlImage.BringToFront();
    
12.  
    
13. #region 截图函数
    
14.     [DllImport("gdi32.dll")] 
    
15.     public static extern IntPtr CreateDC( 
    
16.      string lpszDriver, // driver name驱动名 
    
17.      string lpszDevice, // device name设备名 
    
18.      string lpszOutput, // not used; should be NULL 
    
19.      IntPtr lpInitData // optional printer data 
    
20.      ); 
    
21.     [DllImport("gdi32.dll")] 
    
22.     public static extern int BitBlt( 
    
23.      IntPtr hdcDest, // handle to destination DC目标设备的句柄 
    
24.      int nXDest, // x-coord of destination upper-left corner目标对象的左上角的X坐标 
    
25.      int nYDest, // y-coord of destination upper-left corner目标对象的左上角的Y坐标 
    
26.      int nWidth, // width of destination rectangle目标对象的矩形宽度 
    
27.      int nHeight, // height of destination rectangle目标对象的矩形长度 
    
28.      IntPtr hdcSrc, // handle to source DC源设备的句柄 
    
29.      int nXSrc, // x-coordinate of source upper-left corner源对象的左上角的X坐标 
    
30.      int nYSrc, // y-coordinate of source upper-left corner源对象的左上角的Y坐标 
    
31.      UInt32 dwRop // raster operation code光栅的操作值 
    
32.      );
    
33.     [DllImport("gdi32.dll")] 
    
34.     public static extern IntPtr CreateCompatibleDC( 
    
35.      IntPtr hdc // handle to DC 
    
36.      );
    
37.     [DllImport("gdi32.dll")] 
    
38.     public static extern IntPtr CreateCompatibleBitmap( 
    
39.      IntPtr hdc, // handle to DC 
    
40.      int nWidth, // width of bitmap, in pixels 
    
41.      int nHeight // height of bitmap, in pixels 
    
42.      );
    
43.     [DllImport("gdi32.dll")] 
    
44.     public static extern IntPtr SelectObject( 
    
45.      IntPtr hdc, // handle to DC 
    
46.      IntPtr hgdiobj // handle to object 
    
47.      );
    
48.     [DllImport("gdi32.dll")] 
    
49.     public static extern int DeleteDC( 
    
50.      IntPtr hdc // handle to DC 
    
51.      );
    
52.     [DllImport("user32.dll")] 
    
53.     public static extern bool PrintWindow( 
    
54.      IntPtr hwnd, // Window to copy,Handle to the window that will be copied. 
    
55.      IntPtr hdcBlt, // HDC to print into,Handle to the device context. 
    
56.      UInt32 nFlags // Optional flags,Specifies the drawing options. It can be one of the following values. 
    
57.      );
    
58.     [DllImport("user32.dll")] 
    
59.     public static extern IntPtr GetWindowDC( 
    
60.      IntPtr hwnd 
    
61.      );
    
62.     public Bitmap GetWindow(IntPtr hWnd) 
    
63.     { 
    
64.         IntPtr hscrdc = GetWindowDC(hWnd); 
    
65.         Control control = Control.FromHandle(hWnd); 
    
66.         IntPtr hbitmap = CreateCompatibleBitmap(hscrdc, control.Width, control.Height); 
    
67.         IntPtr hmemdc = CreateCompatibleDC(hscrdc); 
    
68.         SelectObject(hmemdc, hbitmap); 
    
69.         PrintWindow(hWnd, hmemdc, 0); 
    
70.         Bitmap bmp = Bitmap.FromHbitmap(hbitmap); 
    
71.         DeleteDC(hscrdc);//删除用过的对象 
    
72.         DeleteDC(hmemdc);//删除用过的对象 
    
73.         return bmp; 
    
74.     } 
    
75.     #endregion

方法二、给background赋值

1. Bitmap bmp = new Bitmap(this.tabPage12.Width, this.tabPage12.Height);
   
2. //将控件区域显呈到指定位图 
   
3. this.tabPage12.DrawToBitmap(bmp, this.tabPage12.DisplayRectangle); 
   
4. form1.pnlImage.BackgroundImage = (Image)bmp;
   
5. /* 分屏显示座席 */ 
   
6. form1.pnlImage.BackColor = Color.White; 
   
7. form1.pnlImage.BringToFront();

方法三、将某个屏幕位置拷贝到image

1. Image img = new Bitmap(tabPage13.Width, tabPage13.Height); 
   
2. Graphics g = Graphics.FromImage(img); 
   
3. g.CopyFromScreen(Obj.PointToScreen(Point.Empty), Point.Empty, tabPage13.Size); 
   
4. IntPtr dc1 = g.GetHdc(); 
   
5. g.ReleaseHdc(dc1); 
   
6. form1.pnlImage.BackgroundImage = img;
   
7. form1.pnlImage.BringToFront();