MarshalDirectiveException - Method's type signature is not PInvoke compatible

AGorodnov · #1 July 2nd, 2009, 01:44 PM

Hello,
I'm trying to retrieve a structure in C# from a C dll. Really to say I'm not an expert programmer on both C/C#, and will appreciate any comments and suggestions.
Here's a C dll coded structure, to be retrieved..
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 struct MESSAGEE 

{

      int               MsgNo;          

      int               MsgType;       

      char        MsgTypeText[64];

      char        MsgNoText[64];  

      char        MsgText[256];    

};

--
the function to be connected to (C coded)
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 MESSAGEE*  Msg_Listing(

            int         &nMsg,    

            int         Type        

)

--
My code in C# for the structure:
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  [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi, Pack = 1)]

        public struct MESSAGEE 

        {

            Int32 MsgNo;

            Int32 MsgType;

            [MarshalAs(UnmanagedType.LPStr, SizeConst = 64)]

            string MsgTypeText;

            [MarshalAs(UnmanagedType.LPStr, SizeConst = 64)]

            string MsgNoText;

            [MarshalAs(UnmanagedType.LPStr, SizeConst = 256)]

            string MsgText;

        }

--
And a DLL function calling :
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         [DllImport("messagees.dll")] // Connection string

        [return: MarshalAs(UnmanagedType.LPStruct)]

        public static unsafe extern MESSAGEE Msg_Listing([Out]

            Int32 nRules,    // # of defined rules

            Int32 Type    // type of rule checking

            );

--

Thanks a lot in advance!!

MarshalDirectiveException - Method's type signature is not PInvoke compatible

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