C#实现将网页保存成图片的网页拍照功能

本文实例主要实现了网页照相机程序的功能。c#实现将网页保存成图片格式，简单实现网页拍照，主要是基于activex 组件的网页快照类，acitvex 必须实现 iviewobject 接口。因此读者完全可扩展此类将其用于你的c#软件项目中。在此特别感谢作者：随飞提供的代码。

主要功能代码如下：

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;
    }
  }
}