[英]Calling C++ function from JavaScript script running in a web browser control
I have embedded a web browser control in my c++ application. 我在我的c ++应用程序中嵌入了一个Web浏览器控件。 I want javascript running in the web browser control to be able to call a c++ function/method.
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: 我发现有三种方法可以做到这一点:
I want to go with the third option, but I haven't found any working examples on how to do that. 我想第三个选项,但我没有找到任何有关如何做到这一点的工作示例。 Can someone please show me how to do it, or link to a working example on the net somewhere.
有人可以告诉我该怎么做,或链接到某个网上的工作示例。
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 . 最接近我发现的一个例子是Igor Tandetnik在webbrowser_ctl新闻组的一个帖子中的第一个回复。 But I'm afraid I need more help than that.
但我担心我需要更多的帮助。
I'm embedding an IWebBrowser2 control and I am not using MFC, ATL or WTL. 我嵌入了一个IWebBrowser2控件,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. 通过Igor在我之前链接的线程中给出的伪代码,以及代码项目文章“ 从C ++创建JavaScript数组和其他对象 ”中找到的代码,我已经生成了一些代码。
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. 上面的代码一直在运行,所以一切看起来都不错。
I call AddCustomObject when I receive the DISPID_NAVIGATECOMPLETE2 DWebBrowserEvents2 event passing this as *custObj
: 当我收到DISPID_NAVIGATECOMPLETE2 DWebBrowserEvents2事件并将其作为
*custObj
传递时,我调用AddCustomObject:
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,我从未得到“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 GetIDsOfNames
like so: 我像这样实现了
GetIDsOfNames
:
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 转到单独的问题
EDIT 6: 编辑6:
Made a separate question out of the "returning a string" edits. 从“返回字符串”编辑中单独提出一个问题 。 That way I can accept Georg's reply as that answers the original question.
这样我就可以接受Georg的答复,因为它回答了原来的问题。
EDIT 7: 编辑7:
I have gotten a few requests for a fully working, self contained, example implementation. 我已经收到了一些完全工作,自包含的示例实现的请求。 Here it is: https://github.com/Tobbe/CppIEEmbed .
这是: https : //github.com/Tobbe/CppIEEmbed 。 Please fork and improve if you can :)
如果你能:)请分叉和改进:)
You need to implement GetIDsOfNames()
to do something sensible as that function will be called by client code before Invoke()
. 您需要实现
GetIDsOfNames()
来做一些合理的事情,因为在Invoke()
之前客户端代码将调用该函数。
If you have your interfaces in a type library see here for an example. 如果您在类型库中有接口,请参阅此处以获取示例。 If you want to use late-binding instead, you can use
DISPID
s greater DISPID_VALUE
and less than 0x80010000
(all values <= 0
and in the range 0x80010000
through 0x8001FFFF
are reserved): 如果要使用后期绑定,则可以使用
DISPID
更大的DISPID_VALUE
且小于0x80010000
(所有值<= 0
且在0x80010000
到0x8001FFFF
范围内保留):
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 DISPID
s are not supposed to change suddenly, so eg a static map
or constant values should be used. 请注意,
DISPID
不应突然改变,因此例如应使用静态map
或常量值。
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