故事背景：Java組的小伙伴需要一個(gè)能在IE（還是6。。。）下截圖并返回給網(wǎng)頁(yè)的功能，但是IE做起來(lái)很麻煩（可能根本做不到），于是找到我寫(xiě)一個(gè)ActiveX控件實(shí)現(xiàn)此功能，想著可能還有其他小伙伴需要這個(gè)功能，于是就PO出來(lái)，供需要的人使用，當(dāng)然也可以作為學(xué)習(xí)C#編寫(xiě)ActiveX的一個(gè)簡(jiǎn)單入門(mén)教程（VC++效果更好）。
功能截圖如下：
代碼分為兩個(gè)核心部分：1、C#屏幕截圖；2、C#開(kāi)發(fā)ActivX控件。
1、屏幕截圖，這個(gè)在網(wǎng)上找到了一個(gè)只需要5行代碼的實(shí)現(xiàn)（超級(jí)精簡(jiǎn)），當(dāng)然你也可以費(fèi)點(diǎn)功夫?qū)崿F(xiàn)自由區(qū)域截取圖片，截圖后保存到本地，然后使用二進(jìn)制讀取jpg文件，并編碼為base64返回給網(wǎng)頁(yè)
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#開(kāi)發(fā)ActiveX控件，網(wǎng)上示例比較多
先新建一個(gè)類(lèi)庫(kù)，并設(shè)置項(xiàng)目屬性，COM可見(jiàn)
并為COM互注冊(cè)，這樣編譯完了會(huì)自動(dòng)注冊(cè)COM控件
完成設(shè)置后，編寫(xiě)代碼，如下：
using System;using System.Collections.Generic;using System.Text;using System.Runtime.InteropServices;namespace PrintScreenLib{ //為了讓ActiveX控件獲得客戶(hù)端的信任，控件類(lèi)需要實(shí)現(xiàn)一個(gè)名為“IObjectSafety”的接口。先創(chuàng)建該接口（注意，不能修改該接口的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); }} 新建用戶(hù)控件，并派生IObjectSafe接口，接口實(shí)現(xiàn)是固定內(nèi)容
[Guid("61D7F413-A1B2-48A9-B851-5BFBCF50280C")] //使用VS工具里的GUID生成器生成唯一碼 public partial class PSLib : UserControl, IObjectSafety { #region IObjectSafety 成員 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調(diào)用ActiveX控件：
<!DOCTYPE html><html> <head> <title>測(cè)試</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編碼后的圖片 } </script> </head> <body> <OBJECT ID="MyActiveX" WIDTH="120" HEIGHT=20" CLASSID="CLSID:61D7F413-A1B2-48A9-B851-5BFBCF50280C"></OBJECT> <input type="button" value="截圖" onclick="jt();"> <Image id ="img" /> </body></html> 一個(gè)完整的ActvieX控件就完成了，這里沒(méi)有使用到事件，如果使用事件的話會(huì)更加麻煩一點(diǎn)。
下載：屏幕截圖ActivX控件
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