Hi,

I am a new guy in C#.

I try to pass a struct with a point to a mfc dll. But I am failed. Anybody
knows what I must do?

The following is my code:
------------------------------------
C++ dll:
class MyStrStruct
{
public:
int size;
int* buffer;
};

extern "C" bool PASCAL EXPORT fMFCDLL(MyStrStruct* pObj)
{
AFX_MANAGE_STATE(AfxGetStaticModuleState());
// normal function body here

for(int i = 0; i < pObj->size;++i)
{
pObj->buffer[i] += 1;
}

return true;
}

-----------------------------
c#:
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
public class MyStrStruct
{
public int size;
[MarshalAs(UnmanagedType.ByValArray, ArraySubType =
UnmanagedType.I4)]
public int[] buffer;
}

[DllImport("MFCDll.dll", CharSet = CharSet.Auto)]
private static extern bool fMFCDLL([In,Out] MyStrStruct obj);

private void button1_Click(object sender, EventArgs e)
{
try
{
MyStrStruct obj = new MyStrStruct();

obj.size = 10;
obj.buffer = new int[obj.size];

for (int i = 0; i < obj.size; ++i)
{
obj.buffer[i] = i;
}

fMFCDLL(obj);

string strOutput="";
for (int i = 0; i < obj.size; ++i)
{
strOutput += obj.buffer[i].ToString() + " ";
}
MessageBox.Show(strOutput);
}
catch(Exception ex)
{
MessageBox.Show(ex.Message);
}
}
}

Best Regards,
Michael

Hi,

I have found the solution. It is:

public IntPtr buffer;
....
obj.buffer = Marshal.UnsafeAddrOfPinnedArrayElement(ari, 0);

Anyway, thanks.

Best Regards,
Michael

"zhanglr" wrote: