解决C# 截取当前程序窗口指定位置截图的实现方法

[ System.Runtime.InteropServices.DllImportAttribute ( "gdi32.dll" ) ]
private static extern bool BitBlt (
    IntPtr hdcDest , // 目的 DC的句柄
    int nXDest ,
    int nYDest ,
    int nWidth ,
    int nHeight ,
    IntPtr hdcSrc , // 流DC的句柄
    int nXSrc ,
    int nYSrc ,
    System.Int32 dwRop // 光栅的处置数值
) ;

using System ;
using System.Drawing ;
using System.Collections ;
using System.ComponentModel ;
using System.Windows.Forms ;
using System.Data ;
using System.Drawing.Imaging ;
public class Form1 : Form
{
    private Button button1 ;
    private System.ComponentModel.Container components = null ;
public Form1 ( )
{
    //始初化窗体中的各个组件
    InitializeComponent ( ) ;
}
// 肃清程序中使用过的资源
protected override void Dispose ( bool disposing )
{
    if ( disposing )
    {
        if ( components != null )
        {
            components.Dispose ( ) ;
        }
    }
    base.Dispose ( disposing ) ;
}
private void InitializeComponent ( )
{
    button1 = new Button ( );
    SuspendLayout ( ) ;
    button1.Location = new System.Drawing.Point ( 64 , 40 ) ;
    button1.Name = "button1" ;
    button1.Size = new System.Drawing.Size ( 80 , 32 ) ;
    button1.TabIndex = 0 ;
    button1.Text = "捕捉" ;
    button1.Click += new System.EventHandler ( button1_Click ) ;
    AutoScaleBaseSize = new System.Drawing.Size ( 6 , 14 ) ;
    ClientSize = new System.Drawing.Size ( 216 , 125 ) ;
    Controls.Add ( button1 ) ;
    MaximizeBox = false ;
    MinimizeBox = false ;
    Name = "Form1" ;
    Text = "C#捕捉以后屏幕！" ;
    ResumeLayout ( false ) ;
}
//声亮一个API函数
    [ System.Runtime.InteropServices.DllImportAttribute ( "gdi32.dll" ) ]
    private static extern bool BitBlt (
        IntPtr hdcDest , // 目的 DC的句柄
        int nXDest ,
        int nYDest ,
        int nWidth ,
        int nHeight ,
        IntPtr hdcSrc , // 源DC的句柄
        int nXSrc ,
        int nYSrc ,
        System.Int32 dwRop // 光栅的处置数值
    ) ;
static void Main ( )
{
    Application.Run ( new Form1 ( ) ) ;
}
private void button1_Click ( object sender , System.EventArgs e )
{
    //取得当前屏幕的大小
    Rectangle rect = new Rectangle ( ) ;
    rect = Screen.GetWorkingArea ( this ) ;
    //创立一个以以后屏幕为模板的图象
    Graphics g1 = this.CreateGraphics ( ) ;
    //创立以屏幕大小为尺度的位图
    Image MyImage = new Bitmap ( rect.Width , rect.Height , g1 ) ;
    Graphics g2 = Graphics.FromImage ( MyImage ) ;
    //得到屏幕的DC
    IntPtr dc1 = g1.GetHdc ( ) ;
    //得到Bitmap的DC
    IntPtr dc2 = g2.GetHdc ( ) ;
    //调用彼API函数，完成屏幕捕捉
    BitBlt ( dc2 , 0 , 0 , rect.Width , rect.Height , dc1 , 0 , 0 , 13369376 ) ;
    //开释掉屏幕的DC
    g1.ReleaseHdc ( dc1 ) ;
    //开释掉Bitmap的DC
    g2.ReleaseHdc ( dc2 ) ;
    //以JPG白件格局来保留
    MyImage.Save ( @"c:\Capture.jpg" , ImageFormat.Jpeg );
    MessageBox.Show ( "该前屏幕已经保留为C盘的capture.jpg白件！" ) ;
}
}