COM Interop and Array Pointers

[Mike]

I am using a COM DLL function that takes a pointer to the first
element in an array of short values.

Foo(short* array)

COM interop provides that function to me in the .NET world with a "ref
short" parameter.

Foo(ref short array)

It seems that no matter what I try, the function only sees the first
element in the array. Is there a way to get it to see then entire
array? Maybe by using some sort of marshalling I haven't tried yet?

Thanks,
Mike

 

[Eusebiu]

Hello...
If you write short* array is not actually... is a pointer to a memory zone
where is some information (it may be the start of an array).. so don't think
that this is an array...

To call that method correctly, you'll have to marshal the C# array to
unmanaged and send the size of the array.
So you'll have something like this...
//C++
void Foo(short* pArray, unsigned int size){...};

//C#
[DllImport("MyDll.dll")]
public static extern Foo(ref IntPtr arrayPointer, uint size);

To create arrayPointer you'll have to allocate some memory...
short[] myArray;
//init and set array elements

IntPtr arrayPointer = Marshal.AlloHGlobal(myArray.Length *
Marshal.SizeOf(typeof(short));

Marshal.Copy(myArray, 0, arrayPointer, myArray.Length);

//invoke method...
Foo(arrayPointer, myArray.Length);

Hope this helps...