wrapper for c++ to c#

[diembi]

Hello,

I'm new in c#-c++ marshaling and wrappers. I need to use a c++ dll where there are the next header and struct:

extern "C" __declspec(dllexport) int GiveMeData(LPCTSTR sID, CustomerData* pData)


typedef struct CustomerData
{
LPTSTR customerName
LONG customerItems;
}

In C#, is correct the next wrapper?


[DllImport("Customers.dll")]
public static extern int GiveMeData(string sID, ref CustomerData pData);
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
public struct CustomerData
{
public string customerName;
public int customerItems;
}

If isn't correct, how is the best way for do it avoiding possibles heap corruptions, etc?

Thank you!!!!

 

[phinoppix]

You might have a problem with customerName, because of .NET string's immutable nature. It would seem that the native DLL will be setting the value of customerName. You can try substituting that with StringBuilder.

 

[xwb]

You probably need to marshal the strings. I've never used C pointers: only fixed sized arrays. Possibly something like

[DllImport("Customers.dll")]
public static extern int GiveMeData(
   //                                 ,--  Depending on whether you are
   //                                 |    using unicode.  If not use byte
   [MarshalAs(UnmanagedType.LPArray)] char[] sID, 
   ref CustomerData pData);

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
public struct CustomerData
{
   // If array of known size, say 16 then add something like
   // [MarshalAs(UnmanagedType.ByValTStr, SizeConst=16)]
   public string customerName; 
   public int customerItems;
}