wrapper for c++ to c#

diembi · Mar 28, 2013

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 · Apr 11, 2013

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 · Apr 13, 2013

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

Code:

[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;
}

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wrapper for c++ to c#

diembi

Programmer

phinoppix

Programmer

xwb

Programmer

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