windows 从 Web 浏览器控件中运行的 JavaScript 脚本调用 C++ 函数
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Calling C++ function from JavaScript script running in a web browser control
提问by Tobbe
I have embedded a web browser control in my c++ application. I want javascript running in the web browser control to be able to call a c++ function/method.
我在我的 C++ 应用程序中嵌入了一个 Web 浏览器控件。我希望在 Web 浏览器控件中运行的 javascript 能够调用 C++ 函数/方法。
I have found mentions of three ways to do this:
我发现提到了三种方法：
- Implement an ActiveX component that acts as a middle man. (Implementation details here: http://blogs.msdn.com/b/nicd/archive/2007/04/18/calling-into-your-bho-from-a-client-script.aspx)
- Use window.external. (Also discussed in the link above, but no implementation provided)
- Add a custom object to the window object
- 实现充当中间人的 ActiveX 组件。（这里的实现细节：http: //blogs.msdn.com/b/nicd/archive/2007/04/18/calling-into-your-bho-from-a-client-script.aspx）
- 使用 window.external。（也在上面的链接中讨论过，但没有提供实现）
- 向窗口对象添加自定义对象
I want to go with the third option, but I haven't found any working examples on how to do that. Can someone please show me how to do it, or link to a working example on the net somewhere.
我想选择第三个选项，但我还没有找到任何关于如何做到这一点的有效示例。有人可以告诉我如何做，或链接到网络上某处的工作示例。
The closest to an example that I have found is the first reply by Igor Tandetnik in a thread in the webbrowser_ctl news group. But I'm afraid I need more help than that.
我发现的最接近示例的是 Igor Tandetnik 在webbrowser_ctl 新闻组中的一个线程中的第一个回复。但恐怕我需要更多的帮助。
I'm embedding an IWebBrowser2 control and I am not using MFC, ATL or WTL.
我嵌入了一个 IWebBrowser2 控件并且我没有使用 MFC、ATL 或 WTL。
EDIT:
编辑：
Going by the pseudo-code given by Igor in the thread I linked earlier, and code found in the codeproject article "Creating JavaScript arrays and other objects from C++" I've produced some code.
根据 Igor 在我之前链接的线程中给出的伪代码，以及在 codeproject 文章“从 C++ 创建 JavaScript 数组和其他对象”中找到的代码，我生成了一些代码。
void WebForm::AddCustomObject(IDispatch *custObj, std::string name)
{
IHTMLDocument2 *doc = GetDoc();
IHTMLWindow2 *win = NULL;
doc->get_parentWindow(&win);
if (win == NULL) {
return;
}
IDispatchEx *winEx;
win->QueryInterface(&winEx);
if (winEx == NULL) {
return;
}
int lenW = MultiByteToWideChar(CP_ACP, MB_PRECOMPOSED, name.c_str(), -1, NULL, 0);
BSTR objName = SysAllocStringLen(0, lenW);
MultiByteToWideChar(CP_ACP, MB_PRECOMPOSED, name.c_str(), -1, objName, lenW);
DISPID dispid;
HRESULT hr = winEx->GetDispID(objName, fdexNameEnsure, &dispid);
SysFreeString(objName);
if (FAILED(hr)) {
return;
}
DISPID namedArgs[] = {DISPID_PROPERTYPUT};
DISPPARAMS params;
params.rgvarg = new VARIANT[1];
params.rgvarg[0].pdispVal = custObj;
params.rgvarg[0].vt = VT_DISPATCH;
params.rgdispidNamedArgs = namedArgs;
params.cArgs = 1;
params.cNamedArgs = 1;
hr = winEx->InvokeEx(dispid, LOCALE_USER_DEFAULT, DISPATCH_PROPERTYPUT, ¶ms, NULL, NULL, NULL);
if (FAILED(hr)) {
return;
}
}
The code above runs all the way through, so everything looks alright that far.
上面的代码一直运行，所以到目前为止一切看起来都很好。
I call AddCustomObject when I receive the DISPID_NAVIGATECOMPLETE2 DWebBrowserEvents2 event passing this as *custObj:
当我收到 DISPID_NAVIGATECOMPLETE2 DWebBrowserEvents2 事件时，我调用 AddCustomObject 将其传递为*custObj：
class JSObject : public IDispatch {
private:
long ref;
public:
// IUnknown
virtual HRESULT STDMETHODCALLTYPE QueryInterface(REFIID riid, void **ppv);
virtual ULONG STDMETHODCALLTYPE AddRef();
virtual ULONG STDMETHODCALLTYPE Release();
// IDispatch
virtual HRESULT STDMETHODCALLTYPE GetTypeInfoCount(UINT *pctinfo);
virtual HRESULT STDMETHODCALLTYPE GetTypeInfo(UINT iTInfo, LCID lcid,
ITypeInfo **ppTInfo);
virtual HRESULT STDMETHODCALLTYPE GetIDsOfNames(REFIID riid,
LPOLESTR *rgszNames, UINT cNames, LCID lcid, DISPID *rgDispId);
virtual HRESULT STDMETHODCALLTYPE Invoke(DISPID dispIdMember, REFIID riid,
LCID lcid, WORD wFlags, DISPPARAMS *Params, VARIANT *pVarResult,
EXCEPINFO *pExcepInfo, UINT *puArgErr);
};
Noteworthy implementations might be
值得注意的实现可能是
HRESULT STDMETHODCALLTYPE JSObject::QueryInterface(REFIID riid, void **ppv)
{
*ppv = NULL;
if (riid == IID_IUnknown || riid == IID_IDispatch) {
*ppv = static_cast<IDispatch*>(this);
}
if (*ppv != NULL) {
AddRef();
return S_OK;
}
return E_NOINTERFACE;
}
and
和
HRESULT STDMETHODCALLTYPE JSObject::Invoke(DISPID dispIdMember, REFIID riid,
LCID lcid, WORD wFlags, DISPPARAMS *Params, VARIANT *pVarResult,
EXCEPINFO *pExcepInfo, UINT *puArgErr)
{
MessageBox(NULL, "Invoke", "JSObject", MB_OK);
return DISP_E_MEMBERNOTFOUND;
}
Unfortunately I never get the "Invoke" message box when I try to use the "JSObject" object from the javascript code.
不幸的是，当我尝试使用 javascript 代码中的“JSObject”对象时，我从未收到“调用”消息框。
JSObject.randomFunctionName(); // This should give me the c++ "Invoke" message
// box, but it doesn't
EDIT 2:
编辑2：
I implemented GetIDsOfNameslike so:
我GetIDsOfNames是这样实现的：
HRESULT STDMETHODCALLTYPE JSObject::GetIDsOfNames(REFIID riid,
LPOLESTR *rgszNames, UINT cNames, LCID lcid, DISPID *rgDispId)
{
HRESULT hr = S_OK;
for (UINT i = 0; i < cNames; i++) {
std::map<std::wstring, DISPID>::iterator iter = idMap.find(rgszNames[i]);
if (iter != idMap.end()) {
rgDispId[i] = iter->second;
} else {
rgDispId[i] = DISPID_UNKNOWN;
hr = DISP_E_UNKNOWNNAME;
}
}
return hr;
}
and this is my constructor
这是我的构造函数
JSObject::JSObject() : ref(0)
{
idMap.insert(std::make_pair(L"execute", DISPID_USER_EXECUTE));
idMap.insert(std::make_pair(L"writefile", DISPID_USER_WRITEFILE));
idMap.insert(std::make_pair(L"readfile", DISPID_USER_READFILE));
}
with the DISPID_USER_* constants defined as private class members
将 DISPID_USER_* 常量定义为私有类成员
class JSObject : public IDispatch {
private:
static const DISPID DISPID_USER_EXECUTE = DISPID_VALUE + 1;
static const DISPID DISPID_USER_WRITEFILE = DISPID_VALUE + 2;
static const DISPID DISPID_USER_READFILE = DISPID_VALUE + 3;
// ...
};
EDIT 3, 4 and 5:
编辑 3、4 和 5：
Moved to a separate question
移到一个单独的问题
EDIT 6:
编辑 6：
Made a separate questionout of the "returning a string" edits. That way I can accept Georg'sreply as that answers the original question.
做一个单独的问题了“返回一个字符串”的编辑。这样我就可以接受Georg 的回答，因为它回答了最初的问题。
EDIT 7:
编辑 7：
I have gotten a few requests for a fully working, self contained, example implementation. Here it is: https://github.com/Tobbe/CppIEEmbed. Please fork and improve if you can :)
我收到了一些关于完全工作、自包含的示例实现的请求。它是：https://github.com/Tobbe/CppIEEmbed。如果可以，请分叉并改进:)
采纳答案by Georg Fritzsche
You need to implement GetIDsOfNames()to do something sensible as that function will be called by client code before Invoke().
If you have your interfaces in a type library see herefor an example. If you want to use late-binding instead, you can use DISPIDsgreater DISPID_VALUEand less than 0x80010000(all values <= 0and in the range 0x80010000through 0x8001FFFFare reserved):
您需要执行GetIDsOfNames()一些明智的操作，因为该函数将在Invoke().
如果您在类型库中有接口，请参见此处的示例。如果你想使用，而不是后期绑定，你可以用DISPID小号大于DISPID_VALUE和小于0x80010000（所有值<= 0和范围0x80010000，通过0x8001FFFF保留）：
HRESULT GetIDsOfNames(REFIID riid, LPOLESTR *rgszNames, UINT cNames,
LCID lcid, DISPID *rgDispId)
{
HR hr = S_OK;
for (UINT i=0; i<cNames; ++i) {
if (validName(rgszNames)) {
rgDispId[i] = dispIdForName(rgszNames);
} else {
rgDispId[i] = DISPID_UNKNOWN;
hr = DISP_E_UNKNOWNNAME;
}
}
return hr;
}
HRESULT Invoke(DISPID dispIdMember, REFIID riid, LCID lcid, WORD wFlags,
DISPPARAMS *Params, VARIANT *pVarResult, EXCEPINFO *pExcepInfo,
UINT *puArgErr)
{
if (wFlags & DISPATCH_METHOD) {
// handle according to DISPID ...
}
// ...
Note that the DISPIDs are not supposed to change suddenly, so e.g. a static mapor constant values should be used.
请注意，DISPIDs 不应突然更改，因此map应使用例如静态或常量值。
