1、背景
网页本身的功能是有限的,要想实现一些网页本身不支持的功能,比如:网页上的p2p视频播放,就得靠ActiveX这种古老的技术。
2、前提(c#能开发ActiveX吗?)
严格意义上讲,c#是不能生成纯正ocx控件的,我们在vs.net中新建项目时,也找不到专门的"ActiveX项目"新建项,最多也只就能新建"类库"得到一个dll而非ocx(因此我们也无法用传统的regsvr32来注册该dll),但是c#能开发com组件,activeX控件本质上讲跟com是一类技术,所以用c#开发"能够让网页调用的com类库"还是可行的。
3、攻略:
(1)新建一个类库
(2)修改项目的"属性",在“生成”选项中把“输出”中的“为com互操作注册”勾中,然后再到“应用程序”选项中找到“程序集信息”按钮,点击它,在弹出的界面中勾中“使程序集COM可见(M)”
(3) 修改AssemblyInfo.cs,增加[assembly: AllowPartiallyTrustedCallers()],完整内容类似下面这样:
using System.Reflection; using System.Runtime.CompilerServices; using System.Runtime.InteropServices; using System.Security; // General Information about an assembly is controlled through the following // set of attributes. Change these attribute values to modify the information // associated with an assembly. [assembly: AssemblyTitle("ActiveXDemo")] [assembly: AssemblyDescription("")] [assembly: AssemblyConfiguration("")] [assembly: AssemblyCompany("Microsoft")] [assembly: AssemblyProduct("ActiveXDemo")] [assembly: AssemblyCopyright("Copyright ? Microsoft 2009")] [assembly: AssemblyTrademark("")] [assembly: AssemblyCulture("")] [assembly: AllowPartiallyTrustedCallers()] // Setting ComVisible to false makes the types in this assembly not visible // to COM components. If you need to access a type in this assembly from // COM, set the ComVisible attribute to true on that type. [assembly: ComVisible(true)] // The following GUID is for the ID of the typelib if this project is exposed to COM [assembly: Guid("bd585d12-7f22-4b3f-959f-18efbfc53f94")] // Version information for an assembly consists of the following four values: // // Major Version // Minor Version // Build Number // Revision // // You can specify all the values or you can default the Build and Revision Numbers // by using the '*' as shown below: // [assembly: AssemblyVersion("1.0.*")] [assembly: AssemblyVersion("1.0.0.0")] [assembly: AssemblyFileVersion("1.0.0.0")]
using System; using System.Collections.Generic; using System.Text; using System.Runtime.InteropServices; namespace ActiveXDemo { [ComImport, GuidAttribute("CB5BDC81-93C1-11CF-8F20-00805F2CD064")] [InterfaceTypeAttribute(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); } }
using System; using System.Runtime.InteropServices; using System.Threading; using System.Windows.Forms; namespace ActiveXDemo { [Guid("8d7d8518-ca58-4863-b94d-3c616fda7b35")] public partial class MyActiveX : UserControl,IObjectSafety { delegate void D(object obj); public MyActiveX() { InitializeComponent(); } #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 private void MyActiveX_Load(object sender, EventArgs e) { } public void Start(object obj) { for (int i = 0; i < 10; i++) { Thread t = new Thread(new ParameterizedThreadStart(ShowTime)); t.Start(obj.ToString() + ",线程:" + i.ToString()); } } private void button1_Click(object sender, EventArgs e) { Start("Hello World"); } void ShowTime(object obj) { if (this.listBox1.InvokeRequired) { D d = new D(DelegateShowTime); listBox1.Invoke(d, obj); } else { this.listBox1.Items.Add(obj); } } void DelegateShowTime(object obj) { this.listBox1.Items.Add(obj); } } }
#region IObjectSafety 成员 ... #endregion这一段的内容是固定的,不要修改,其它内容根据自己的业务要求自行修改,另外类前面要加上Guid的标识,以便网页调用时,能用CLSID="xxx"来调用
基本上这样弄完后,就可以在网页中,用类似下面这样的代码来本机调用了:
注意:c#定义的public方法,如果想直接让js调用,只能返回string,DateTime,int,double这一类基本值类型,其它返回类型比如array,object,在js中要么直接报错,要么得到null
<object id="x" classid="clsid:8d7d8518-ca58-4863-b94d-3c616fda7b35"></object> <hr /> <input type="button" value="调用ActiveX中的多线程方法" onclick="fnTest()" /> <script type="text/javascript"> var fnTest = function(){ var x = document.getElementById("x"); x.Start("这是js中的参数"); } </script>
4.安装部署
前面已经提到了,c#开发的(伪)"ActiveX"控件并非纯正的ocx,所以只能用RegAsm.Exe xxx.dll来进行程序集的注册,这里要注意一点:在开发机上,项目编译后vs.net会自动将bin\debug\xxx.dll调用regasm注册,但在别人机器上就不行了,为了能在调试时模拟其它机器的运行结果,可以在编译后,手动用类似 regAsm.exe D:\MyDoc\ActiveXDemo\output\ActiveXDemo.dll /u 来反注册(在vs.net命令行模式下)
当然,如果您不勾选3.(2)中所说的“为com互操作注册”,vs编译时便不会自动注册,但是这样调试起来不太方便,另外注册/反注册时的RegAsm.exe要起开发环境中的版本一致(比如你开发时设置是64位版本,那么反注册也要用64位版本的RegAsm.exe)
另外,我们也不可能在每个客户机上手动用RegAsm.exe来帮客户注册,所以我们还得新建安装项目来做一个安装包,这个比较简单,直接新建一个"其他项目类型-->安装和部署-->安装项目"即可
然后在安装项目上,右键"添加"-->"项目输出"-->"主输出"-->在项目下拉框中选择activex所对应的项目即可.
注意:"主输出来自xxx"的属性栏中,有一个"Register"必须选择"vsdrpCOM"
另外还有一个问题,可能是我机器的个别现象,每次activex项目有修改时,建议最好手动清除安装项目debug目录下的文件,再重新生成安装项目,否则有时候会发现activex修改了,但是安装包中包含的dll还是未修改过的版本。
后话:c#开发的东西是运行于.net 框架之上的,就好比java开发的东西必须要java runtime才能运行一样,利用本文方法开发出来的dll也必须要安装.net框架才能跑起来,幸好最新的win7中已经集成了.net框架,当然您如果对于庞大的.net框架安装程序很敏感,仍然觉得纯正的ocx更好的话,建议还是用vb/delphi/c++这一类老牌的开发工具/语言实现。