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自由区域截取图片，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
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。
dy("nrwz");
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