C#实现将网页保存成图片的网页拍照功能

using System;using System.Collections.Generic;using System.Text;using System.Runtime.InteropServices;using System.Runtime.InteropServices.ComTypes;using System.Drawing;using System.Windows.Forms;namespace SnapLibrary{  /// <summary>  /// ActiveX 组件快照类，用于网页拍照，将网页保存成图片  /// AcitveX 必须实现 IViewObject 接口  /// 作者:随飞  /// </summary>  public class Snapshot  {    /// <summary>    /// 取快照    /// </summary>    /// <param name="pUnknown">Com 对象</param>    /// <param name="bmpRect">图象大小</param>    /// <returns></returns>    public Bitmap TakeSnapshot(object pUnknown, Rectangle bmpRect)    {      if (pUnknown == null)        return null;      //必须为com对象      if (!Marshal.IsComObject(pUnknown))        return null;      //IViewObject 接口      SnapLibrary.UnsafeNativeMethods.IViewObject ViewObject = null;      IntPtr pViewObject = IntPtr.Zero;      //内存图      Bitmap pPicture = new Bitmap(bmpRect.Width, bmpRect.Height);      Graphics hDrawDC = Graphics.FromImage(pPicture);      //获取接口      object hret = Marshal.QueryInterface(Marshal.GetIUnknownForObject(pUnknown),        ref UnsafeNativeMethods.IID_IViewObject, out pViewObject);      try      {        ViewObject = Marshal.GetTypedObjectForIUnknown(pViewObject, typeof(SnapLibrary.UnsafeNativeMethods.IViewObject)) as SnapLibrary.UnsafeNativeMethods.IViewObject;        //调用Draw方法        ViewObject.Draw((int)DVASPECT.DVASPECT_CONTENT,          -1,          IntPtr.Zero,          null,          IntPtr.Zero,          hDrawDC.GetHdc(),          new NativeMethods.COMRECT(bmpRect),          null,          IntPtr.Zero,          0);        Marshal.Release(pViewObject);      }      catch (Exception ex)      {        Console.WriteLine(ex.Message);        throw ex;      }      //释放      hDrawDC.Dispose();      return pPicture;    }  }}