Received SafeArrayTypeMismatchException when passing a struct by ref to an unmanaged function call

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C

C#

interop

unmanaged

My unmanaged function signature is as follows:

HRESULT extern WINAPI WFSStartUp ( DWORD dwVersionsRequired, LPWFSVERSION lpWFSVersion);

Where LPWFSVERSION
I is a pointer to struct

I declared the following struct

[StructLayout(LayoutKind.Sequential)]
 public class WFSVERSION
 {
     public int            wVersion;
     public int            wLowVersion;
     public int            wHighVersion;
     public char[]           szDescription;
     public char[]           szSystemStatus;
 };

[DllImport(@"C:\WINDOWS\system32\msxfs.dll")]


[return: MarshalAs(UnmanagedType.I4)]
public static extern int WFSStartUp(double dwVersionsRequired, [MarshalAs(UnmanagedType.LPStruct)] ref WFSVERSION rc);

When calling the function in my C# application I get
SafeArrayTypeMismatchException

WFSVERSION rc = new WFSVERSION();


rc.szDescription = new char[256];
rc.szSystemStatus = new char[256];

int result = WFSStartUp(130819, ref rc);

i understand that the struct needs to be of IDispatch interface type so I attempted

to do the following:

WFSVERSION rc = new WFSVERSION();
DispatchWrapper dispArray = new DispatchWrapper((object)rc);

But then it gives me a compile error saying that my cast is incorrect. Please advise. I ran out of ideas.