如何检索 COM 类的接口 ID 以便可以将其传递给 CoCreateInstance?

How to retrieve the Interface ID of a COM class so that it can be passed to CoCreateInstance?(如何检索 COM 类的接口 ID 以便可以将其传递给 CoCreateInstance?)

问题描述

我想以编程方式检索任何类的接口 ID，以便可以将其传递给 CoCreateInstance.非常感谢任何帮助！

I want to programaticly retrieve the Interface ID for any class so that I can pass it to CoCreateInstance. Any help is very much appreciated!!

请参阅下面的我如何得到这个":

HRESULT hResult;
CLSID ClassID;
void *pInterface;

if(!(hResult = SUCCEEDED(CoInitialize(NULL))))
{
    return 1;
}

if(S_OK == CLSIDFromProgID(OLESTR("Scripting.FileSystemObject"), &ClassID))
{
    hResult = CoCreateInstance(ClassID, NULL, CLSCTX_INPROC_SERVER,
        <<How Do I Get This?>>, (LPVOID *)&pInterface);
}

CoUninitialize();

感谢您的所有帮助，现在似乎可以正常工作了！:

HRESULT hResult;
CLSID ClassID;
IClassFactory *pClf;
void *pVdb;

if(!(hResult = SUCCEEDED(CoInitialize(NULL))))
{
    return 1;
}

if(SUCCEEDED(CLSIDFromProgID(OLESTR("Scripting.FileSystemObject"), &ClassID))
{
    IDispatch *pDispatch;

    if(SUCCEEDED(CoCreateInstance(ClassID, NULL, CLSCTX_INPROC_SERVER,
            IID_IDispatch, (void **)&pDispatch))
    {
        OLECHAR *sMember = L"FileExists";

        DISPID idFileExists;

        if(SUCCEEDED(pDispatch->GetIDsOfNames(
                IID_NULL, &sMember, 1, LOCALE_SYSTEM_DEFAULT, &idFileExists))
        {
            unsigned int puArgErr = 0;

            VARIANT VarResult;
            EXCEPINFO pExcepInfo;

            VariantInit(&VarResult); 
            VariantInit(&pExcepInfo); 

            DISPPARAMS pParams;
            memset(&pParams, 0, sizeof(DISPPARAMS)); 
            pParams.cArgs = 1; 

            VARIANT Arguments[1];
            VariantInit(&Arguments[0]); 

            pParams.rgvarg = Arguments; 
            pParams.cNamedArgs = 0;
            pParams.rgvarg[0].vt = VT_BSTR;
            pParams.rgvarg[0].bstrVal = SysAllocString(L"C:\Test.txt");

            hResult = pDispatch->Invoke(  
                idFileExists,
                IID_NULL,
                LOCALE_SYSTEM_DEFAULT,
                DISPATCH_METHOD,
                &pParams,
                &VarResult,
                &pExcepInfo,
                &puArgErr
            );

            SysFreeString(pParams.rgvarg[0].bstrVal);

            printf("File Exists? %d
", abs(VarResult.boolVal));
        }

        pDispatch->Release();
    }
}

CoUninitialize();

推荐答案

你需要预先知道你需要什么接口.这可以从产品规范、SDK 头文件中获得，或者您可以将 COM 对象的 TLB 导入到您的项目中.

You need to know upfront what interface you ask for. This you get from the product specifications, from SDK header files, or you can import the TLB of the COM object into your project.

最简单的方法是使用 #import

这篇关于如何检索 COM 类的接口 ID 以便可以将其传递给 CoCreateInstance?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持编程学习网！