C#調用Windows API函數截圖

界面如下：

下面放了一個PictureBox

 

首先是聲明函數：

//這里是調用 Windows API函數來進行截圖
        //首先導入庫文件
        [System.Runtime.InteropServices.DllImportAttribute("gdi32.dll")]

        //聲明函數
        private static extern IntPtr CreateDC
        (
            string Driver,   //驅動名稱
            string Device,   //設備名稱
            string Output,   //無用，可以設定為null
            IntPtr PrintData //任意的打印機數據
         );


        [System.Runtime.InteropServices.DllImportAttribute("gdi32.dll")]
        private static extern bool BitBlt(
            IntPtr hdcDest,     //目標設備的句柄
            int XDest,          //目標對象的左上角X坐標
            int YDest,          //目標對象的左上角的Y坐標
            int Width,          //目標對象的寬度
            int Height,         //目標對象的高度
            IntPtr hdcScr,      //源設備的句柄
            int XScr,           //源設備的左上角X坐標
            int YScr,           //源設備的左上角Y坐標
            Int32 drRop         //光柵的操作值

            );

截圖按鈕事件代碼：

private void button1_Click(object sender, EventArgs e)
        {
            //創建顯示器的DC
            IntPtr dcScreen = CreateDC("DISPLAY", null, null, (IntPtr)null);

            //由一個指定設備的句柄創建一個新的Graphics對象
            Graphics g1 = Graphics.FromHdc(dcScreen);
            int tmpWidth, tmpHeigth;


            //獲得保存圖片的質量
            long level = long.Parse(this.textBox5.Text);

            //如果是全屏捕獲
            if(this.radioButton1.Checked == true)
            {
                tmpWidth = Screen.PrimaryScreen.Bounds.Width;
                tmpHeigth = Screen.PrimaryScreen.Bounds.Height;
                Image MyImage = new Bitmap(tmpWidth, tmpHeigth, g1);

                //創建位圖圖形對象
                Graphics g2 = Graphics.FromImage(MyImage);
                //獲得窗體的上下文設備
                IntPtr dc1 = g1.GetHdc();
                //獲得位圖文件的上下文設備
                IntPtr dc2 = g2.GetHdc();

                //寫入到位圖
                BitBlt(dc2, 0, 0, tmpWidth, tmpHeigth, dc1, 0, 0, 13369376);
                
                //釋放窗體的上下文設備
                g1.ReleaseHdc(dc1);
                //釋放位圖的上下文設備
                g2.ReleaseHdc(dc2);


                //保存圖像並顯示
                SaveImageWithQuality(MyImage,level);
                this.pictureBox1.Image = MyImage;

            }
            else
            {
                int X = Convert.ToInt32(this.textBox1.Text);
                int Y = Convert.ToInt32(this.textBox2.Text);
                int Width = Convert.ToInt32(this.textBox3.Text);
                int Height = Convert.ToInt32(this.textBox4.Text);

                Image Myimage = new Bitmap(Width, Height,g1);
                Graphics g2 = Graphics.FromImage(Myimage);
                IntPtr dc1 = g1.GetHdc();
                IntPtr dc2 = g2.GetHdc();

                BitBlt(dc2,0,0,Width,Height,dc1,X,Y,13369376);
                g1.ReleaseHdc(dc1);
                g2.ReleaseHdc(dc2);

                SaveImageWithQuality(Myimage, level);
                this.pictureBox1.Image = Myimage;


            }
        }

設置圖片質量的函數，詳細介紹：http://www.cnblogs.com/zhaotianff/p/5570321.html

 //保存圖片時設置質量
        private void SaveImageWithQuality(Image bmp,long level)
        {
            
           
            ImageCodecInfo jgpEncoder = GetEncoder(ImageFormat.Jpeg);
            System.Drawing.Imaging.Encoder myEncoder =
                System.Drawing.Imaging.Encoder.Quality;
            EncoderParameters myEncoderParameters = new EncoderParameters(1);
            EncoderParameter myEncoderParameter = new EncoderParameter(myEncoder, level);
            myEncoderParameters.Param[0] = myEncoderParameter;
            bmp.Save(@"test.jpg", jgpEncoder, myEncoderParameters);

            

        }





        private ImageCodecInfo GetEncoder(ImageFormat format)
        {

            ImageCodecInfo[] codecs = ImageCodecInfo.GetImageDecoders();

            foreach (ImageCodecInfo codec in codecs)
            {
                if (codec.FormatID == format.Guid)
                {
                    return codec;
                }
            }
            return null;
        }

運行效果：

可惜把自己也截出來了，正在尋找方法不把自己截出來，哈哈。