将COM事件暴露给VBScript（ATL） [英] Exposing COM events to VBScript (ATL)
问题描述
我的控件定义如下：
class ATL_NO_VTABLE CSetACLCOMServer：
public CComObjectRootEx< CComSingleThreadModel>
public CComCoClass< CSetACLCOMServer& CLSID_SetACLCOMServer>
public IConnectionPointContainerImpl< CSetACLCOMServer> ，
public CProxy_ISetACLCOMServerEvents< CSetACLCOMServer>
public IDispatchImpl< ISetACLCOMServer& IID_ISetACLCOMServer& LIBID_SetACLCOMLibrary / * wMajor = * / 1，/ * wMinor = * / 0>
public IProvideClassInfo2Impl& CLSID_SetACLCOMServer，& DIID__ISetACLCOMServerEvents& LIBID_SetACLCOMLibrary> / * VBS中的事件支持* /
{
public：
BEGIN_COM_MAP（CSetACLCOMServer）
COM_INTERFACE_ENTRY（ISetACLCOMServer）
COM_INTERFACE_ENTRY（IDispatch）
COM_INTERFACE_ENTRY（IConnectionPointContainer）
COM_INTERFACE_ENTRY（IProvideClassInfo）
COM_INTERFACE_ENTRY（IProvideClassInfo2）
END_COM_MAP（）
BEGIN_CONNECTION_POINT_MAP（CSetACLCOMServer）
CONNECTION_POINT_ENTRY（__ uuidof _ISetACLCOMServerEvents））
END_CONNECTION_POINT_MAP（）
[...]
在VBScript中，我使用COM对象：
set objSetACL = WScript.CreateObject（SetACL.SetACL， SetACL_）
'从SetACL COM服务器捕获并打印作为事件传递（触发）的消息。
'此函数的名称后缀（MessageEvent）必须与SetACL定义的事件名称
'相同。
'前缀（SetACL_）可以在调用WScript.CreateObject
时自由设置。SetCallateEvent（Message）
WScript.Echo消息
end sub
IDL的相关部分如下所示：
[
对象，
uuid（E1B57CA5-FD7F-4304-BC0A-8BEBDE231D53），
双，
不可扩展，
pointer_default（唯一）
helpstring（SetACL COM Interface）
]
接口ISetACLCOMServer：IDispatch
{
};
[
uuid（00D4DCD3-02B9-4A71-AB61-2283504620C8），
版本（1.0），
helpstring（SetACL类型库）
]
库SetACLCOMLibrary
{
importlib（stdole2.tlb）;
[
uuid（35F76182-7F52-4D6A-BD6E-1317345F98FB），
helpstring（SetACL Event Interface）
]
dispinterface _ISetACLCOMServerEvents
{
属性：
方法：
[id（1），helpstring（接收将在命令行版本的屏幕上显示的字符串消息）
void MessageEvent（[in] BSTR message）;
};
[
uuid（13379563-8F21-4579-8AC7-CBCD488735DB），
helpstring（SetACL COM Server），
]
coclass SetACLCOMServer
{
[default] interface ISetACLCOMServer;
[default，source] dispinterface _ISetACLCOMServerEvents;
};
};
问题：SetACL_MessageEvent从未被调用。
我尝试过：
- 阅读这个知识库文章我添加了IProvideClassInfo2的实现，但没有帮助。
- 此常见问题解答提示出站接口不应定义为双接口。我从我的界面定义中删除了dual，但没有帮助。
- 我发现这个SO问题似乎描述了一个类似的问题。没有给出答案，只是一个解决方法。
更新1：
我现在知道它在哪里失败，但不是为什么：在_ISetACLCOMServerEvents_CP.h中的fire event方法中，调用Invoke失败，并带有E_UNEXPECTED。这是行：
hr = pConnection-> Invoke（1，IID_NULL，LOCALE_USER_DEFAULT，DISPATCH_METHOD，& params，NULL ，NULL，NULL）;
解决方案：
问题是我从COM对象的后台线程中调用了事件触发函数，换句话说是从错误的公寓调用。
实现 IProvideClassInfo2 应该是足够的（虽然我的印象是它应该可以工作，即使没有它）。我从模板创建了一个简约的ATL项目作为样本。这是ATL DLL + COM类+一个方法和事件+ IProvideClassInfo2 ：
测试 .vbs 是以下：
功能Test_Event（文本）
WScript.Echo事件：+文本
结束函数
Dim Test
Set Test = WScript.CreateObject（AlaxInfo.VbsEvents.Foo，Test_）
Test.Method（Event Fun）
方法本身是：
code> // IFoo
STDMETHOD（方法）（BSTR sText）throw（）
{
ATLTRACE（atlTraceCOM，4，_T（sText \％s\ \\\
），CString（sText））;
ATLVERIFY（SUCCEEDED（Fire_Event（sText）））;
返回S_OK;
}
执行此操作时，输出为：
如果您从后台线程中触发，我以为您可能在示例项目中遇到事件问题。您还可以使用调试器进行项目，并检查 Fire _ 呼叫中是否有任何错误。
I have built a COM server DLL in C++ with ATL by using the "ATL simple object" wizard. I followed Microsoft's ATLDLLCOMServer example. Everything works well except for one thing: I do not receive COM events in VBScript. I do receive the events in C#. I had events working in VBScript in an earlier MFC-based implementation as ActiveX control.
My control is defined like this:
class ATL_NO_VTABLE CSetACLCOMServer :
public CComObjectRootEx<CComSingleThreadModel>,
public CComCoClass<CSetACLCOMServer, &CLSID_SetACLCOMServer>,
public IConnectionPointContainerImpl<CSetACLCOMServer>,
public CProxy_ISetACLCOMServerEvents<CSetACLCOMServer>,
public IDispatchImpl<ISetACLCOMServer, &IID_ISetACLCOMServer, &LIBID_SetACLCOMLibrary, /*wMajor =*/ 1, /*wMinor =*/ 0>,
public IProvideClassInfo2Impl<&CLSID_SetACLCOMServer, &DIID__ISetACLCOMServerEvents, &LIBID_SetACLCOMLibrary> /* Required for event support in VBS */
{
public:
BEGIN_COM_MAP(CSetACLCOMServer)
COM_INTERFACE_ENTRY(ISetACLCOMServer)
COM_INTERFACE_ENTRY(IDispatch)
COM_INTERFACE_ENTRY(IConnectionPointContainer)
COM_INTERFACE_ENTRY(IProvideClassInfo)
COM_INTERFACE_ENTRY(IProvideClassInfo2)
END_COM_MAP()
BEGIN_CONNECTION_POINT_MAP(CSetACLCOMServer)
CONNECTION_POINT_ENTRY(__uuidof(_ISetACLCOMServerEvents))
END_CONNECTION_POINT_MAP()
[...]
In VBScript I use the COM object like this:
set objSetACL = WScript.CreateObject("SetACL.SetACL", "SetACL_")
' Catch and print messages from the SetACL COM server which are passed (fired) as events.
' The name postfix of this function (MessageEvent) must be identical to the event name
' as defined by SetACL.
' The prefix (SetACL_) can be set freely in the call to WScript.CreateObject
sub SetACL_MessageEvent (Message)
WScript.Echo Message
end sub
The relevant parts of the IDL look like this:
[
object,
uuid(E1B57CA5-FD7F-4304-BC0A-8BEBDE231D53),
dual,
nonextensible,
pointer_default(unique),
helpstring("SetACL COM Interface")
]
interface ISetACLCOMServer : IDispatch
{
};
[
uuid(00D4DCD3-02B9-4A71-AB61-2283504620C8),
version(1.0),
helpstring ("SetACL Type Library")
]
library SetACLCOMLibrary
{
importlib("stdole2.tlb");
[
uuid(35F76182-7F52-4D6A-BD6E-1317345F98FB),
helpstring ("SetACL Event Interface")
]
dispinterface _ISetACLCOMServerEvents
{
properties:
methods:
[id(1), helpstring("Receives string messages that would appear on the screen in the command line version")]
void MessageEvent([in] BSTR message);
};
[
uuid(13379563-8F21-4579-8AC7-CBCD488735DB),
helpstring ("SetACL COM Server"),
]
coclass SetACLCOMServer
{
[default] interface ISetACLCOMServer;
[default, source] dispinterface _ISetACLCOMServerEvents;
};
};
The problem: SetACL_MessageEvent never gets called.
What I have tried:
- After reading this KB article I added the implementation of IProvideClassInfo2, but that did not help.
- This FAQ mentions that outgoing interface should not defined as a dual interfaces. I removed the "dual" from my interface definition, but that did not help.
- I found this SO question that seems to describe a similar problem. An answer was never given, only a workaround.
UPDATE 1:
I know now where it is failing, but not why: in the fire event method in _ISetACLCOMServerEvents_CP.h the call to Invoke fails with E_UNEXPECTED. This is the line:
hr = pConnection->Invoke(1, IID_NULL, LOCALE_USER_DEFAULT, DISPATCH_METHOD, ¶ms, NULL, NULL, NULL);
Solution:
The problem was that I called the event firing function from a background thread in the COM object, in other words from the wrong apartment.
Implementation of IProvideClassInfo2 should be sufficient (though I was under impression that it should work even without it). I created a minimalistic ATL project from template as a sample. This is ATL DLL + COM Class + a method and an event + IProvideClassInfo2:
Source code [SVN, Browser Friendly] + Win32 Binary.
Test .vbs is the following:
Function Test_Event(Text)
WScript.Echo "Event: " + Text
End Function
Dim Test
Set Test = WScript.CreateObject("AlaxInfo.VbsEvents.Foo", "Test_")
Test.Method("Event Fun")
And the method itself is:
// IFoo
STDMETHOD(Method)(BSTR sText) throw()
{
ATLTRACE(atlTraceCOM, 4, _T("sText \"%s\"\n"), CString(sText));
ATLVERIFY(SUCCEEDED(Fire_Event(sText)));
return S_OK;
}
And having executed this, the output is:
I thought you might be having issues with events in your sample project if you are firing them from a background thread. You can also step your project with debugger and check if you have any errors in the Fire_ call.
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