[.NET]如何打印视窗某块区域

今天在论坛看到一个问题,是问如何打印winform的某块区域

想一想我从来没玩过打印相关的功能,就尝试了一下

我的思路是要打印某个区块,那就将那个区块当成图片打印下来就好了

搜寻了一下打印的范例,以及用GDI撷取视窗

解决了这个问题

下面是打印的截图,我打印出视窗rect(30,30,100,100)这个范围

 

原始WinForm:

 

 

印表机打印结果：

 

using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using System.Drawing.Printing; using System.Runtime.InteropServices; namespace WinTest { public partial class Form1 : Form { Image _ActiveFormImage; public Form1() { InitializeComponent(); } private void button1_Click(object sender, EventArgs e) { MessageBox.Show("test"); } private void panel2_Paint(object sender, PaintEventArgs e) { } protected void PrintActiveForm(object sender, EventArgs e) { //ToolStripMenuItem MenuItem = (ToolStripMenuItem)sender; //MessageBox.Show(MenuItem.Name); PrintDialog PD = new PrintDialog(); PrinterSettings PS = new PrinterSettings(); PrintDocument PrtDoc = new PrintDocument(); //_ActiveFormImage = SetSeg_Library.SetCapture.Form(this); Rectangle rt = new Rectangle(0,0,this.Width,this.Height); _ActiveFormImage = Image.FromHbitmap(GDI32.Window(this.Handle,rt).GetHbitmap()); PrtDoc.PrintPage += new PrintPageEventHandler(PrtDoc_PrintPage); PD.Document = PrtDoc; PD.ShowDialog(); PrtDoc.Print(); } void PrtDoc_PrintPage(object sender, PrintPageEventArgs e) { Rectangle rt = new Rectangle(30,30,100,100); e.Graphics.DrawImageUnscaledAndClipped(this._ActiveFormImage,rt); } } public class USER32 { public const int SM_CXSCREEN = 0; public const int SM_CYSCREEN = 1; [DllImport("user32.dll", EntryPoint = "GetDesktopWindow")] public static extern IntPtr GetDesktopWindow(); [DllImport("user32.dll", EntryPoint = "GetDC")] public static extern IntPtr GetDC(IntPtr ptr); [DllImport("user32.dll", EntryPoint = "GetSystemMetrics")] public static extern int GetSystemMetrics(int abc); [DllImport("user32.dll", EntryPoint = "GetWindowDC")] public static extern IntPtr GetWindowDC(Int32 ptr); [DllImport("user32.dll", EntryPoint = "ReleaseDC")] public static extern IntPtr ReleaseDC(IntPtr hWnd, IntPtr hDc); } // end class USER32 public class GDI32 { public const int SRCCOPY = 13369376; [DllImport("gdi32.dll", EntryPoint = "DeleteDC")] public static extern IntPtr DeleteDC(IntPtr hDc); [DllImport("gdi32.dll", EntryPoint = "DeleteObject")] public static extern IntPtr DeleteObject(IntPtr hDc); [DllImport("gdi32.dll", EntryPoint = "BitBlt")] public static extern bool BitBlt(IntPtr hdcDest, int xDest, int yDest, int wDest, int hDest, IntPtr hdcSource, int xSrc, int ySrc, int RasterOp); [DllImport("gdi32.dll", EntryPoint = "CreateCompatibleBitmap")] public static extern IntPtr CreateCompatibleBitmap(IntPtr hdc, int nWidth, int nHeight); [DllImport("gdi32.dll", EntryPoint = "CreateCompatibleDC")] public static extern IntPtr CreateCompatibleDC(IntPtr hdc); [DllImport("gdi32.dll", EntryPoint = "SelectObject")] public static extern IntPtr SelectObject(IntPtr hdc, IntPtr bmp); //public static Bitmap Control(System.Windows.Forms.Control ctl) //{ // return Control(ctl, false, false); // capture entire control //} public static Bitmap Window(IntPtr handle, Rectangle r) { return Window(handle, r.X, r.Y, r.Width, r.Height); } /// <summary> /// Captures the window or part thereof to a bitmap image. /// </summary> /// <param name="wndHWND">window handle</param> /// <param name="x">x location in window</param> /// <param name="y">y location in window</param> /// <param name="width">width of capture area</param> /// <param name="height">height of capture area</param> /// <returns>window bitmap</returns> public static Bitmap Window(IntPtr wndHWND, int x, int y, int width, int height) { IntPtr wndHDC = USER32.GetDC(wndHWND); // get context for window // create compatibile capture context and bitmap IntPtr capHDC = GDI32.CreateCompatibleDC(wndHDC); IntPtr capBMP = GDI32.CreateCompatibleBitmap(wndHDC, width, height); // make sure bitmap non-zero if (capBMP == IntPtr.Zero) // if no compatible bitmap { USER32.ReleaseDC(wndHWND, wndHDC); // release window context GDI32.DeleteDC(capHDC); // delete capture context return null; // return null bitmap } // select compatible bitmap in compatible context // copy window context to compatible context // select previous bitmap back into compatible context IntPtr prvHDC = (IntPtr)GDI32.SelectObject(capHDC, capBMP); GDI32.BitBlt(capHDC, 0, 0, width, height, wndHDC, x, y, GDI32.SRCCOPY); GDI32.SelectObject(capHDC, prvHDC); // create GDI+ bitmap for window Bitmap bmp = System.Drawing.Image.FromHbitmap(capBMP); // release window and capture resources USER32.ReleaseDC(wndHWND, wndHDC); // release window context GDI32.DeleteDC(capHDC); // delete capture context GDI32.DeleteObject(capBMP); // delete capture bitmap // return bitmap image to user return bmp; // return bitmap } } // end class GDI32 }