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从COM接口中的函数返回多个值

idl return-value com c++

GTAVLover · 技术社区 · 7 年前

我做了一项研究,并为实现了一个包装器函数 GetWindowRect API,它运行良好。但它目前只能通过 SAFEARRAY

我这样宣布:

[id(10)] HRESULT WinAPI_GetWindowRect([in] VARIANT hWnd, [out, retval] SAFEARRAY(VARIANT) *lpRect);

STDMETHOD(WinAPI_GetWindowRect)(VARIANT hWnd, SAFEARRAY **lpRect);

和实施:

STDMETHODIMP CWinAPI::WinAPI_GetWindowRect(VARIANT hWnd, SAFEARRAY **lpRect {

    CComSafeArray<VARIANT> CCSA_RECT;
    RECT Rect;
    HRESULT HResult;

    if (!lpRect) { return E_INVALIDARG; }

    *lpRect = nullptr;

    int Result = (int)GetWindowRect(VariantToHWND(hWnd), &Rect);
    //   ^ I ALSO WANT TO RETURN THIS RESULT TOO

    if (Result != 0)
    {
        HResult = CCSA_RECT.Create(4, 0);
        assert(HResult == S_OK);

        CCSA_RECT[0] = Rect.left;
        CCSA_RECT[1] = Rect.top;
        ...
    }
    else
    { ... }
}

[out, retval] 值,那么有没有关于如何返回此值的建议( Result

当我试着这样归还时:

[id(10)] HRESULT WinAPI_GetWindowRect([in] VARIANT hWnd, [out] SAFEARRAY(VARIANT) *lpRect, [out, retval] VARIANT *Result);

STDMETHOD(WinAPI_GetWindowRect)(VARIANT hWnd, SAFEARRAY **lpRect, VARIANT *Result);

按如下方式分配:

Result->intVal = (int)GetWindowRect(VariantToHWND(hWnd), &Rect);

Type mismatch 尝试使用VBScript时,下面的VBScript行出错:

Dim lpRect, Result: Result = WINAPI.WinAPI_GetWindowRect(AutoItX3.WinGetHandle("[CLASS:ConsoleWindowClass]"), lpRect)

我想要这个成为 [out] 参数和 后果 作为返回值。

1 回复 | 直到 7 年前

GTAVLover 7 年前

我通过使用 VARIANT [out] 参数如下:

[id(10)] HRESULT WinAPI_GetWindowRect([in] VARIANT hWnd, [out] VARIANT *Result, [out, retval] SAFEARRAY(VARIANT) *lpRect);

STDMETHOD(WinAPI_GetWindowRect)(VARIANT hWnd, VARIANT *Result, SAFEARRAY **lpRect);

STDMETHODIMP CWinAPI::WinAPI_GetWindowRect(VARIANT hWnd, VARIANT *Result, SAFEARRAY **lpRect) {

    CComSafeArray<VARIANT> CCSA_RECT;
    RECT Rect;
    HRESULT HResult;

    if (!lpRect) { return E_INVALIDARG; }

    *lpRect = nullptr;

    VariantInit(Result);
    Result->vt = VT_I2;

    Result->intVal = (int)GetWindowRect(VariantToHWND(hWnd), &Rect);

    if (Result->intVal != 0)
    {...}
    else
    {...}

}

这已使用以下VBScript进行了测试:

Dim AutoItX3: Set AutoItX3 = WScript.CreateObject("AutoItX3.Control")
Dim WINAPI: Set WINAPI = WScript.CreateObject("WinAPIWrapperLib.WINAPI")

Dim lpRect, Result: lpRect = WINAPI.WinAPI_GetWindowRect(AutoItX3.WinGetHandle("[CLASS:ConsoleWindowClass]"), Result)

WScript.Echo "GetWindowRect returned: " + CStr(Result)

If CInt(Result) <> 0 Then
    For iNum = 0 To UBound(lpRect)
        WScript.Echo CStr(lpRect(iNum))
    Next
End If

WScript.Echo(CStr(WINAPI.WinAPI_GetLastErrorMessage))

但是,我仍然无法使用 SAFEARRAY [输出] [输出] Result 像 [out, retval]

[id(10)] HRESULT WinAPI_GetWindowRect([in] VARIANT hWnd, [out] SAFEARRAY(VARIANT) *lpRect, [out, retval] VARIANT *Result);

仍然导致 Type mismatch 错误