MarshalDirectiveException

[korrea80]

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!

[Richard Andrew x64]

There is another way you can marshal the return type from that function. First, declare the return type from the C function to be a pointer to the GetPluginData structure instead of the structure itself. Declare the return type as an IntPtr in C#, and then use the functions in the Marshal class to read the structure from unmanaged memory into a managed structure.

The difficult we do right away... ...the impossible takes slightly longer.

[korrea80]

Hi! Thanks for the info Richard. The solution was write for Hans Passans in StackOverflow:

    \[DllImport("RBRPlugin.dll", CallingConvention = CallingConvention.Cdecl, EntryPoint = "GetDataArray")\]
    public static extern GetPluginData GetDataArray(int number);
    
    \[StructLayoutAttribute(LayoutKind.Sequential)\]
    public struct GetPluginData
    {
        public unsafe fixed int data\[22\];
    }

    public GetPluginData temp1 = new GetPluginData();

    private void button1\_Click(object sender, EventArgs e)
    {
        GetPluginData test = GetDataArray(1);
        temp1 = test;
        unsafe
        {
            fixed (GetPluginData\* p = &temp1)
            {
                p->data\[0\] = 1;
            }
        }
    }

Like you read, the principal problem was the array in GetPluginData struct, it must be fixed. Thaks!