C API的excelDNA内存管理

问题描述

我试图通过方法XlCall.TryExcel从excelDna调用xlfCaller，有时我得到XlReturnStackOvfl，我发现了一些解决此问题的方法：1。在此站点：https://docs.microsoft.com/en-us/office/client-developer/excel/xlfcaller，它表示必须在xlfCaller，2之后在https://docs.excel-dna.net/excel-c-api/处调用xlFree。它表明“ Excel-DNA负责C API调用的所有类型转换和内存管理。 ”，所以我想知道，我需要致电xlFree吗？

解决方法

excelDna总是在调用excel c API之后再调用xlFree，因此我们无需再次调用xlFree。下面是excelDna的源代码：

private unsafe static int TryExcelImpl4(int xlFunction,out object result,params object[] parameters)
    {
        int xlReturn;

        // Set up the memory to hold the result from the call
        XlOper resultOper = new XlOper();
        resultOper.xlType = XlType.XlTypeEmpty;
        XlOper* pResultOper = &resultOper;  // No need to pin for local struct

        // Special kind of ObjectArrayMarshaler for the parameters (rank 1)
        using (XlObjectArrayMarshaler paramMarshaler = new XlObjectArrayMarshaler(1,true))
        {
            XlOper** ppOperParameters = (XlOper**)paramMarshaler.MarshalManagedToNative(parameters);
            xlReturn = Excel4v(xlFunction,pResultOper,parameters.Length,ppOperParameters);
        }

        // pResultOper now holds the result of the evaluated function
        // Get ObjectMarshaler for the return value
        ICustomMarshaler m = XlObjectMarshaler.GetInstance("");
        result = m.MarshalNativeToManaged((IntPtr)pResultOper);
        // And free any memory allocated by Excel
        Excel4v(xlFree,(XlOper*)IntPtr.Zero,1,&pResultOper);
    
        return xlReturn;
    }