[Ray Linn]用Visual Studio 2008开发IE BHO(浏览器帮助对象) 之三

接下来,我们要为IE增加一个按钮(注意不是toolbar,toolbar要复杂得多),基本这是一个注册表的魔术.打开RayBHO.rgs, 添加

HKLM
{
	NoRemove Software
	{
		NoRemove Microsoft
		{
			NoRemove 'Internet Explorer'
			{
				NoRemove Extensions
				{
					ForceRemove '{1AC31710-6759-484f-A129-A70C55485DA1}'
					{
						val ButtonText = s 'Hello,World'
						val Icon = s '%MODULE%,201'
						val HotIcon = s '%MODULE%,202'
						val CLSID = s '{1FBA04EE-3024-11d2-8F1F-0000F87ABD16}'
						val ClsidExtension = s '{057F3E68-6C2E-40A5-A641-E8CF9D6766F3}'
						val 'Default Visible' = s 'yes'
					}
				}
			}
		}
	}
}

当然,你也可以把这一项放在HKCU(Current User)下,这样的话,该Button只对当前用户起作用.

这些注册表项说明如下:

ForceRemove '{1AC31710-6759-484f-A129-A70C55485DA1}' -- 该extersion的CLSID,请自己用GUID这个程序生成.

val ButtonText = s 'Hello,World' // 按钮上的文字说明

val Icon = s '%MODULE%,201' // 按钮的图标,可以是icon的绝对路径,也可以和我的例子一样从资源文件里加载.

val HotIcon = s '%MODULE%,202'// 鼠标悬停时按钮的图标,与Icon类似.

val CLSID = s '{1FBA04EE-3024-11d2-8F1F-0000F87ABD16}' //该CLSID意思为可执行,此值有特定含义,请小心修改.

val ClsidExtension = s '{057F3E68-6C2E-40A5-A641-E8CF9D6766F3}' // 这个是RayBHO的CLSID,即表示该按钮的动作连接到RayBHO这个com上,具体值有所不同,必须查询你自己的rgs文件得到.

val 'Default Visible' = s 'yes'//按钮可见.

当然你也可以不使用COM来响应按钮的动作,另外两个键Exec和Script,可以设置响应的程序或者脚本..这个不是重点.

现在编译,然后从IE的自定义工具栏将这个按钮拖出来...如图所示:




点点看.....结果呢? 当然是不起作用!

因为除以上步骤外，该com 对象还必须实现 IOleCommandTarget接口。

IOleCommandTarget包含QueryStatus和Exec两个方法，其中QueryStatus方法会被IE调用来获得当前菜单的状态.当工具条按钮被点击时，com 对象的 IOleCommandTarget::exec 方法被调用，此时ncmdid 的值为 1；当菜单项被点击时，ncmdid 的值为 2。这样开发者就能区分工具条按钮和菜单项这两个不同操作

首先让CRayBHO继承IOleCommandTarget接口,最后我们得到这样得一个继承树

class ATL_NO_VTABLE CRayBHO :
	public CComObjectRootEx<CComSingleThreadModel>,
	public CComCoClass<CHelloWorldBHO, &CLSID_HelloWorldBHO>,
	public IObjectWithSiteImpl<CHelloWorldBHO>,
	public IDispatchImpl<IHelloWorldBHO, &IID_IHelloWorldBHO, &LIBID_HelloWorldPluginLib, /*wMajor =*/ 1, /*wMinor =*/ 0>,
	public IDispEventImpl<1,CHelloWorldBHO,&DIID_DWebBrowserEvents2,&LIBID_SHDocVw,1,1>,
	public IOleCommandTarget

再COM_MAP里增加

COM_INTERFACE_ENTRY(IOleCommandTarget)

最终得到

	BEGIN_COM_MAP(CHelloWorldBHO)
		COM_INTERFACE_ENTRY(IHelloWorldBHO)
		COM_INTERFACE_ENTRY(IObjectWithSite)
		COM_INTERFACE_ENTRY(IOleCommandTarget)
		COM_INTERFACE_ENTRY(IDispatch)
	END_COM_MAP()

声明IOleCommandTarget的两个方法

	// IOleCommandTarget
	STDMETHOD(Exec)(const GUID*, DWORD nCmdID, DWORD, VARIANTARG*, VARIANTARG* pvaOut);
	STDMETHOD(QueryStatus)(const GUID* pguidCmdGroup, ULONG cCmds, OLECMD prgCmds[], OLECMDTEXT* pCmdText);

然后实现之,基本我们的重点放在Exec方法上...所以先给出QueryStatus的实现

STDMETHODIMP CRayBHO::QueryStatus(const GUID* pguidCmdGroup, ULONG cCmds, OLECMD prgCmds[], OLECMDTEXT* pCmdText)
{
	if (cCmds == 0) return E_INVALIDARG;
	if (prgCmds == 0) return E_POINTER;
	prgCmds[0].cmdf = OLECMDF_ENABLED;
	
	return S_OK;
}

在Exce方法中,可以放入你的响应逻辑,或者更简单的,只是一个MessageBox响应. 这里我给出一段实际的Video Player的代码,这个代码可以为按钮添加下拉菜单,而这个菜单实际是保存在资源文件中的!并且你可以看到如何在Exce响应菜单上点击事件.

STDMETHODIMP CRayBHO::Exec(const GUID*, DWORD nCmdID, DWORD, VARIANTARG*, VARIANTARG*)
{
	if(m_spUnkSite == 0 || m_spWebBrowser == 0) return S_OK;
	HRESULT hRes = S_OK;

	CComPtr<IDispatch>        pDocDisp;
	CComQIPtr<IHTMLDocument2> pHtmlDoc2;
	hRes = m_spWebBrowser->get_Document(&pDocDisp);

	if(SUCCEEDED(hRes) && pDocDisp)
	{
		hRes = pDocDisp->QueryInterface(IID_IHTMLDocument2, (void**)&pHtmlDoc2);
		if(SUCCEEDED(hRes) && pHtmlDoc2)
		{
			SHANDLE_PTR nBrowser = 0;
			m_spWebBrowser->get_HWND(&nBrowser);
			HWND hWndParent = (HWND)nBrowser;

			POINT pt;
			GetCursorPos(&pt);

			HINSTANCE hInstance = _AtlBaseModule.GetModuleInstance();

			HMENU hMenu = LoadMenu(hInstance,MAKEINTRESOURCE(IDR_MENU_POPUP));
			HMENU hMenuTrackPopup = GetSubMenu(hMenu, 0);
			
			if(hMenuTrackPopup && hWndParent)
			{
				BOOL bIsChevron = FALSE;
				HWND hWndMenuParent = NULL;
				HWND hWndToolBar = NULL;
				
				hWndMenuParent = hWndParent;
				hWndToolBar = WindowFromPoint(pt);
				
				if(m_bIsIe7)
				{
					HWND hWndIe7ActiveTab = hWndParent;
					HWND hWnd = GetWindow(hWndParent, GW_CHILD);

					// looking for the Internet Explorer_Server window
					// this window should be a parent for TrackPopupMenu
					if(hWnd)
					{
						TCHAR szClassName[MAX_PATH];
						while(hWnd)
						{
							memset(szClassName,0,MAX_PATH);
							GetClassName(hWnd, szClassName, MAX_PATH);
							if(_tcscmp(szClassName,_T("TabWindowClass"))==0)
							{
								// the active tab should be visible
								if(IsWindowVisible(hWnd))
								{
									hWnd = GetWindow(hWnd, GW_CHILD);
									while(hWnd)
									{
										memset(szClassName,0,MAX_PATH);
										GetClassName(hWnd, szClassName, MAX_PATH);

										if(_tcscmp(szClassName,_T("Shell DocObject View"))==0)
										{
											hWnd = FindWindowEx(hWnd, NULL, _T("Internet Explorer_Server"), NULL);
											if(hWnd) hWndIe7ActiveTab = hWnd;
											break;
										}
										hWnd = GetWindow(hWnd, GW_HWNDNEXT);
									}
								}
							}
							hWnd = GetWindow(hWnd, GW_HWNDNEXT);
						}
					}

					if(hWndIe7ActiveTab) hWndMenuParent = hWndIe7ActiveTab;

					//strHWndMenuParent = _ltoa(hWndMenuParent, 10);
				}

				int nIDCommand = -1;
				BOOL bRightAlign = FALSE;
				if(hWndToolBar)
				{
					ScreenToClient(hWndToolBar,&pt);
					int nButton = (int)::SendMessage(hWndToolBar, TB_HITTEST, 0, (LPARAM)&pt);
					if(nButton>0)
					{
						TBBUTTON pTBBtn;
						memset(&pTBBtn,0,sizeof(TBBUTTON));
						if(::SendMessage(hWndToolBar, TB_GETBUTTON, nButton, (LPARAM)&pTBBtn))
						{
							nIDCommand = pTBBtn.idCommand;
							RECT rcButton;
							if(::SendMessage(hWndToolBar,TB_GETRECT,nIDCommand,(LPARAM)&rcButton))
							{
								pt.x = rcButton.left;
								pt.y = rcButton.bottom;
								ClientToScreen(hWndToolBar,&pt);

								RECT rcWorkArea;
								SystemParametersInfo(SPI_GETWORKAREA,0,(LPVOID)&rcWorkArea,0);
								if(rcWorkArea.right-pt.x<150)
								{
									bRightAlign = TRUE;
									pt.x = rcButton.right;
									pt.y = rcButton.bottom;
									ClientToScreen(hWndToolBar,&pt);
								}
							}
						}
					}
					else
					{
						GetCursorPos(&pt);
						bIsChevron = TRUE;
					}
				}

				UINT nFlags = TPM_NONOTIFY|TPM_RETURNCMD|TPM_LEFTBUTTON;
				if(bRightAlign) nFlags |= TPM_RIGHTALIGN;
				else nFlags |= TPM_LEFTALIGN;

				// draw pressed button
				if(nIDCommand!=-1 && !bIsChevron) ::SendMessage(hWndToolBar, TB_PRESSBUTTON, nIDCommand,  MAKELPARAM(1,0));
				// popup the menu
				int nCommand = TrackPopupMenu(hMenuTrackPopup, nFlags, pt.x, pt.y, 0, hWndMenuParent, 0);
				// release the button
				if(nIDCommand!=-1 && !bIsChevron) ::SendMessage(hWndToolBar, TB_PRESSBUTTON, nIDCommand,  MAKELPARAM(0,0));
				
				//CStringArray* m_EvNameArr = new CStringArray();
				//m_EvNameArr->Add(strHWndMenuParent);

				BOOL bFound = FALSE;
				switch (nCommand)
				{
				case ID_CHIMP:
					{
						MessageBox(hWndParent,_T("Play Video"),_T("IEVideo --Ray"), MB_OK|MB_ICONEXCLAMATION);
					}
					break;
				case ID_SELECT:
					{
						MessageBox(hWndParent,_T("Select Video"),_T("IEVideo --Ray"), MB_OK|MB_ICONEXCLAMATION);

					}
					break;
				case ID_STOP:
					{
						MessageBox(hWndParent,_T("Stop Video"),_T("IEVideo --Ray"), MB_OK|MB_ICONEXCLAMATION);
					}
					break;
				case ID_ABOUT:
					{	
						MessageBox(hWndParent,_T("About IEVideo"),_T("IEVideo --Ray"), MB_OK|MB_ICONEXCLAMATION);
					}
					break;
				}
			}
		}
	}
	return S_OK;
}

最后的效果如下:




很有意思的是, 我被认为是windows的粉丝,但其实我工作里搞的是linux的driver. 论坛里的风气常常喜欢比较A比较B,或者痛斥A痛斥B, 但你深入了解了么?