C#编写ActiveX网页截图控件

故事背景：java组的小伙伴需要一个能在ie（还是6。。。）下截图并返回给网页的功能，但是ie做起来很麻烦（可能根本做不到），于是找到我写一个activex控件实现此功能，想着可能还有其他小伙伴需要这个功能，于是就po出来，供需要的人使用，当然也可以作为学习c#编写activex的一个简单入门教程（vc++效果更好）。
功能截图如下：

 

代码分为两个核心部分：1、c#屏幕截图；2、c#开发activx控件。
 1、屏幕截图，这个在网上找到了一个只需要5行代码的实现（超级精简），当然你也可以费点功夫实现*区域截取图片，截图后保存到本地，然后使用二进制读取jpg文件，并编码为base64返回给网页       

 public string printscreen()
    {
      image baseimage = new bitmap(screen.primaryscreen.bounds.width, screen.primaryscreen.bounds.height);
      graphics g = graphics.fromimage(baseimage);
      g.copyfromscreen(new point(0, 0), new point(0, 0), screen.allscreens[0].bounds.size);
      g.dispose();
      baseimage.save("d:\\screen.jpg", imageformat.jpeg);
      stream file = new filestream("d:\\screen.jpg", filemode.open);
      binaryreader bw = new binaryreader(file);
      var buffer = new byte[file.length];
      bw.read(buffer, 0, buffer.length);
      bw.close();
      string b64 = convert.tobase64string(buffer);
      return b64;
    }

2、c#开发activex控件，网上示例比较多
先新建一个类库，并设置项目属性，com可见 

并为com互注册，这样编译完了会自动注册com控件

完成设置后，编写代码，如下： 

using system;
using system.collections.generic;
using system.text;
using system.runtime.interopservices;

namespace printscreenlib
{
 //为了让activex控件获得客户端的信任，控件类需要实现一个名为“iobjectsafety”的接口。先创建该接口（注意，不能修改该接口的guid值）
 [comimport, guid("cb5bdc81-93c1-11cf-8f20-00805f2cd064")]
 [interfacetype(cominterfacetype.interfaceisiunknown)]
 public interface iobjectsafety
 {
 [preservesig]
 int getinterfacesafetyoptions(ref guid riid, [marshalas(unmanagedtype.u4)] ref int pdwsupportedoptions, [marshalas(unmanagedtype.u4)] ref int pdwenabledoptions);

 [preservesig()]
 int setinterfacesafetyoptions(ref guid riid, [marshalas(unmanagedtype.u4)] int dwoptionsetmask, [marshalas(unmanagedtype.u4)] int dwenabledoptions);
 }
} 

新建用户控件，并派生iobjectsafe接口，接口实现是固定内容 

 [guid("61d7f413-a1b2-48a9-b851-5bfbcf50280c")] //使用vs工具里的guid生成器生成唯一码
 public partial class pslib : usercontrol, iobjectsafety
 {
 #region iobjectsafety 成员
 private const string _iid_idispatch = "{00020400-0000-0000-c000-000000000046}";
 private const string _iid_idispatchex = "{a6ef9860-c720-11d0-9337-00a0c90dcaa9}";
 private const string _iid_ipersiststorage = "{0000010a-0000-0000-c000-000000000046}";
 private const string _iid_ipersiststream = "{00000109-0000-0000-c000-000000000046}";
 private const string _iid_ipersistpropertybag = "{37d84f60-42cb-11ce-8135-00aa004bb851}";

 private const int interfacesafe_for_untrusted_caller = 0x00000001;
 private const int interfacesafe_for_untrusted_data = 0x00000002;
 private const int s_ok = 0;
 private const int e_fail = unchecked((int)0x80004005);
 private const int e_nointerface = unchecked((int)0x80004002);

 private bool _fsafeforscripting = true;
 private bool _fsafeforinitializing = true;


 public int getinterfacesafetyoptions(ref guid riid, ref int pdwsupportedoptions, ref int pdwenabledoptions)
 {
  int rslt = e_fail;

  string strguid = riid.tostring("b");
  pdwsupportedoptions = interfacesafe_for_untrusted_caller | interfacesafe_for_untrusted_data;
  switch (strguid)
  {
  case _iid_idispatch:
  case _iid_idispatchex:
   rslt = s_ok;
   pdwenabledoptions = 0;
   if (_fsafeforscripting == true)
   pdwenabledoptions = interfacesafe_for_untrusted_caller;
   break;
  case _iid_ipersiststorage:
  case _iid_ipersiststream:
  case _iid_ipersistpropertybag:
   rslt = s_ok;
   pdwenabledoptions = 0;
   if (_fsafeforinitializing == true)
   pdwenabledoptions = interfacesafe_for_untrusted_data;
   break;
  default:
   rslt = e_nointerface;
   break;
  }

  return rslt;
 }

 public int setinterfacesafetyoptions(ref guid riid, int dwoptionsetmask, int dwenabledoptions)
 {
  int rslt = e_fail;

  string strguid = riid.tostring("b");
  switch (strguid)
  {
  case _iid_idispatch:
  case _iid_idispatchex:
   if (((dwenabledoptions & dwoptionsetmask) == interfacesafe_for_untrusted_caller) &&
    (_fsafeforscripting == true))
   rslt = s_ok;
   break;
  case _iid_ipersiststorage:
  case _iid_ipersiststream:
  case _iid_ipersistpropertybag:
   if (((dwenabledoptions & dwoptionsetmask) == interfacesafe_for_untrusted_data) &&
    (_fsafeforinitializing == true))
   rslt = s_ok;
   break;
  default:
   rslt = e_nointerface;
   break;
  }

  return rslt;
 }
 #endregion 

ie调用activex控件： 

<!doctype html>
<html>
 <head>
 <title>测试</title>
 
 <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
 <meta http-equiv="description" content="this is my page">
 <meta http-equiv="content-type" content="text/html; charset=utf-8">
 <script>
 function jt(){
  var str="";
  try
  {
  var obj = document.getelementbyid("myactivex"); 
   str=obj.printscreen();
  }
  catch(e)
  {
  alert(e);
  return;
  }

  var img=document.getelementbyid("img");
  img.src="data:image/jpeg;base64,"+str;//接受base64编码后的图片
 }
 </script>
 </head>
 
 <body>
 <object id="myactivex" width="120" height=20" classid="clsid:61d7f413-a1b2-48a9-b851-5bfbcf50280c"></object>
 <input type="button" value="截图" onclick="jt();">
 <image id ="img" />
 </body>
</html> 

一个完整的actviex控件就完成了，这里没有使用到事件，如果使用事件的话会更加麻烦一点。

下载：屏幕截图activx控件

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