COM Component Development Practices (eight)---multithreaded ActiveX controls and automatic resizing of ActiveX controls (bottom)

Disclaimer: This code is based on CodeProject's article, "A Complete ActiveX Web control Tutorial," and therefore also follows code Project Open License (Cpol).

In the previous article, COM Component Development Practice (VII)---Multithreaded ActiveX controls and automatic resizing of ActiveX controls (top) describes the basic requirements for using multithreading in ActiveX controls and presents a simple threading model, but there are unexpected problems. This article will try to give a feasible solution to the problem, and solve the second problem mentioned above.

In fact, the idea of the solution is also very simple, I have already thought of the beginning, is to use the thread postmessage to send a custom message to inform the main thread, the specific event has occurred, the demand main thread to respond. It's not a great idea, but I'm very scared of threading postmessage because it was the problem in a previous project that led to a memory leak, so the scheme was rejected by me at the outset.

All the way to find a solution can not be, had to CSDN forum on the post for the master, the specific discussion please refer to this thread:

Http://topic.csdn.net/u/20081226/17/9bf0ae08-c54d-4934-b1b2-91baa27ff76e.html

See Jameshooo (Hu Pehua) after the reply, or decided to return to the starting point, try to use postmessage this scheme.

First, two events are customized to indicate operation success and operation failure

#define WM_OPTSUCCESS wm_app+101//Operation successful

#define WM_OPTFAILED wm_app+102//operation failed

Then the callback function becomes very simple and requires only the post corresponding event.

/////////////////////
//回调函数
/////////////////////////
void CMyActiveXCtrl::OnSuccesful()
{//操作成功
　　this->PostMessage(WM_OPTSUCCESS,(WPARAM)NULL,(LPARAM)NULL);
}

void CMyActiveXCtrl::OnFailed()
{//操作失败
　　this->PostMessage(WM_OPTFAILED,(WPARAM)NULL,(LPARAM)NULL);
}

Overload the message-handling function WindowProc, in which you call an external JavaScript function or fire an event that the external page can respond to.

LRESULT CMyActiveXCtrl::WindowProc(UINT msg,WPARAM wParam,LPARAM lParam)
{
　　switch (msg)
　　{
　　case WM_OPTSUCCESS:
　　　　{//操作成功，通知外部页面
　　　　　　CString strOnLoaded("OnLoaded");
　　　　　　this->CallJScript(strOnLoaded);
　　　　　　return 0;
　　　　}
　　case WM_OPTFAILED:
　　　　{//操作失败，通知外部页面
　　　　　　//这里不写了，同上面
　　　　}
　　}
　　return　 COleControl::WindowProc(msg,wParam,lParam);
}

To add the start work thread code to the OnCreate function:

int CMyActiveXCtrl::OnCreate(LPCREATESTRUCT lpCreateStruct)
{
　　if (COleControl::OnCreate(lpCreateStruct) == -1)
　　　　return -1;
　　m_MainDialog.Create(IDD_MAINDIALOG,this);
　　pThread.SetICallBack(this);//设置主线程回调函数
　　pThread.Start();//启动工作线程
　　return 0;
}

Overload the OnClose function by adding code to close the worker thread:

void CMyActiveXCtrl::OnClose(DWORD dwSaveOption)
{
　　pThread.Stop(true);//强行关闭工作线程
　　COMRELEASE(pWebBrowser);
　　COMRELEASE(pHTMLDocument);
　　COleControl::OnClose(dwSaveOption);
}