C# MarshalException C code

Hi all!.

I would like use unmanaged code from C in C#.

I built a DLL with C code with this functions:

struct GetPluginData
{
int data[22];
};

DLLEXPORT extern "C" __declspec (dllexport) GetPluginData GetDataArray(int number);

In C# I've got this code:
[StructLayoutAttribute(LayoutKind.Sequential, Pack=1)]
public unsafe struct GetPluginData
{
/// int[22]
[MarshalAsAttribute(UnmanagedType.ByValArray, SizeConst = 22, ArraySubType = UnmanagedType.I4)]
public int[] data;
}

[DllImport("RBRPlugin.dll", CallingConvention = CallingConvention.StdCall, EntryPoint = "GetDataArray")]
[return: MarshalAs(UnmanagedType.Struct)]
public static extern GetPluginData GetDataArray(int number);

In button event or othe place code, I wrote this:
GetPluginData tes = GetDataArray(1);

And I'm getting the error: The type signature of this method is not PInvoke compatible.

I'm looking for information throught google, but no result found...

Thanks in advance!

You can't return structs from PInvoke methods.

You'll have to do it like this :

Code:

---

// C++
struct GetPluginData
{
int data[22];
};

DLLEXPORT extern "C" __declspec (dllexport) void GetDataArray(int number, GetPluginData *pData);

---

And in c#

Code:

---

[StructLayoutAttribute(LayoutKind.Sequential, Pack=1)]
public unsafe struct GetPluginData
{
    [MarshalAsAttribute(UnmanagedType.ByValArray, SizeConst = 22,  ArraySubType = UnmanagedType.I4)]
    public int[] data;
}

[DllImport("RBRPlugin.dll", CallingConvention = CallingConvention.CDecl, EntryPoint = "GetDataArray")]
public static extern void GetDataArray(int number, ref GetPluginData val);

---

Also note the calling convention is CDecl by default for __declspec(dllexport). The extern "C" means the method name exported by the dll isn't decorated.

Darwen.