Create C# structure for CvMat.data union or any way to access it in C#

I need to access 'data' property EmguCV MCvMat structure. But that property is a pointer(IntPtr). I found that structure for this property(data) is an union. It's like this:

union Data
{
    char* ptr;     // Data pointer for an unsigned char matrix
    short* s;      // Data pointer for a short matrix
    int* i;        // Data pointer for an integer matrix
    float* fl;     // Data pointer for a float matrix
    double* db;    // Data pointer for a double matrix
} Data;

I tried 开发者_StackOverflow中文版to create a structure for this in C#:

[StructLayout(LayoutKind.Explicit)]
struct MCvMatData
{
    [FieldOffset(0)]
    public char[] ptr;     // Data pointer for an unsigned char matrix
    [FieldOffset(0)]
    public short[] s;      // Data pointer for a short matrix
    [FieldOffset(0)]
    public int[] i;        // Data pointer for an integer matrix
    [FieldOffset(0)]
    public float[] fl;     // Data pointer for a float matrix
    [FieldOffset(0)]
    public double[] db;    // Data pointer for a double matrix
}

And then convert it using Marshel,

MCvMat mat = (MCvMat)Marshal.PtrToStructure(pMat, typeof(MCvMat));
MCvMatData matdata = (MCvMatData)Marshal.PtrToStructure(mat.data, typeof(MCvMatData));

But this gives me an exception. What I need to do is:

• Create data structure in C# for access this pointer or
• Any other way to access MCvMat.data property

I've published a Visual Studio 2010 solution on SkyDrive. It dmonstrates un-marshalling such a structure.

I'll try the MarshalAs attribute when I have more time. Usually, in such situations, I would implement an adapter layer in C++ to make it easier to transfer data between unmanaged and managed code.