I have .NET Dll with a C# method, which I use in Excel VBA. It's being called through a COM-wrapper from VBA. The method takes among others, two double arrays as arguments.
When the double arrays are defined in VBA with a lower boundary of 1, and being passed to the C# method though COM, Excel fails with following error:
Runtime error 5(Invalid procedure call or argument)
Although it may sound crazy, I would want to be able to pass a VBA/COM array with lower boudary of 1 to C# .NET. Is this possible?
This is how the C# function is declared:
public double LinearInterpolation( double[] psaXvector, double[] psaYvector, double Xvalue){The COM-wrapper in C#
[Guid("CE93D637-0673-4EBC-8FFA-6CE162959262")] [ComVisible(true)] [InterfaceType(ComInterfaceType.InterfaceIsDual)] public interface IMixedTools { [DispId(1)] [return: MarshalAs(UnmanagedType.R8)] double LinearInterpolation( [MarshalAs(UnmanagedType.SafeArray)]double[] psaXvector, [MarshalAs(UnmanagedType.SafeArray)]double[] psaYvector, [MarshalAs(UnmanagedType.R8)]double Xvalue);This is what the generated .tlh file looks like
struct __declspec(uuid("ce93d637-0673-4ebc-8ffa-6ce162959262"))IMixedTools : IDispatch{ virtual HRESULT __stdcall LinearInterpolation ( /*[in]*/ SAFEARRAY * psaXvector, /*[in]*/ SAFEARRAY * psaYvector, /*[in]*/ double Xvalue, /*[out,retval]*/ double * pRetVal ) = 0;The calling VBA code
Dim mixu As Object Set mixu = CreateObject("TlibCOM.CMixedTools") Dim Xarr() As Double Dim Yarr() As Double ReDim Xarr(1 To 4) As Double ReDim Yarr(1 To 4) As Double Dim x As Double Xarr(1) = 1 Xarr(2) = 2 Xarr(3) = 5 Xarr(4) = 7.5 Yarr(1) = 14 Yarr(2) = 9 Yarr(3) = 4 Yarr(4) = -3 x = 4 result = mixu.LinearInterpolation(Xarr, Yarr, x) Set mixu = NothingIf I define the arrays with lower boundaries of 0, the function will work. But I have a quite large legacy codebase where arrays may be defined either with 0 or 1 as lower boundary of arrays, so the functions having arrays as arguments would need to be able to handle this.
The C# .NET DLL is a library of methods, replacing legacy ATL COM functions. Previously this was not an issue whether the double array passed from VBA was having a low boundary of 1 or 0.
Is there a way to go round this limitation, so that VBA can pass an array with the low boundary of 1, to C# methods in a DLL?
