structures in structure

[juhaka]

Hi, again!

How can I make a new structure, which contains others structures?
I have two structures, which contains only native types (byte, uint) and I have a need for a new structure, which contains these my own datatypes (structures).

[ StructLayout( LayoutKind.Sequential )]
public struct MSettings_def
{
public byte MFormat;
[MarshalAs( UnmanagedType.ByValArray, SizeConst=4)]
public byte[] MObjects;
[MarshalAs( UnmanagedType.ByValArray, SizeConst=4)]
public byte[] ONumber;
public byte Brightness;
}

[ StructLayout( LayoutKind.Sequential )]
public struct Rparam_def
{
public byte UpperPoint;
public byte LowerPoint;
public byte MaxSpeed;
public byte MinSpeed;
[MarshalAs( UnmanagedType.ByValArray, SizeConst=4)]
public uint[] Valves;
}

When I use Marshal.SizeOf(struct_object), I get the sizes of the structures, 10 and 20 bytes

Now, when I make a new structure:

public struct Param_def
{
[MarshalAs( UnmanagedType.ByValArray, SizeConst=10)]
byte[] Name;
[MarshalAs( UnmanagedType.ByValArray, SizeConst=80)]
byte[] Comment;
MSettings_def msf;
[MarshalAs( UnmanagedType.ByValArray, SizeConst=10)]
Rparam_def[] rpd;
}

If I call Marshal.SizeOf(param_def_object) -method, I get an error:Converter.Param_def can not be marshaled as an unmanaged structure; no meaningful size or offset can be computed.


What's wrong in my Param_def -structure?

br. Juha Ka

 

[akaBigKahuna]

I am getting similar error when including an array of structures in another structure:

"can not be marshaled as an unmanaged structure; no meaningful size or offset can be computed. at System.Runtime.InteropServices.Marshal.SizeOf(Object structure) "

juhaka, did you ever figure out how to resolve this error?

 

[juhaka]

I never resolved this error. I gave up with structs and did it with classes.

public class MSettings_def
{
public byte MFormat = 0;
public byte[] MObjects = new byte[4];
public byte[] ONumber = new byte[4];
public byte Brightness = 0;
}

public class Rparam_def
{
public byte UpperPoint = 0;
public byte LowerPoint = 0;
public byte MaxSpeed = 0;
public byte MinSpeed = 0;
public uint[] Valves = new uint[10];
}

public class Param_def
{
byte[] Name = new byte[20];
byte[] Comment = new byte[80];
MSettings_def msf = new MSetting_def();
Rparam_def[] rpd = new Rparam_def[10];
}

It was pity, because now I haven't be able to do type casting from c++ struct to c# struct....