DllImport c# "Attempted to read or write protected memory" error

Hi all,

I am using DllImport to invoke an external C dll's function.

C header file has the following definition

_EASY_IMPORT_OR_EXPORT_ eint EASYCALL setSessionElement(eint SessionId, PCSTR lpszElementName, PCSTR lpszElementValue)

C# import statement

   [DllImport("EasyclaimC.dll", CharSet = CharSet.Auto, EntryPoint = "setSessionElement", CallingConvention = CallingConvention.StdCall, SetLastError = true)]
   public static extern long setSessionElement(
       long SessionId,
       [MarshalAs(UnmanagedType.LPWStr)]
       string ElementName,
       [MarshalAs(UnmanagedType.LPWStr)]
        string ElementValue);

Invoke:

ECAPI.setSessionElement(aSessionId,"LocationID", minorCustId);

which fails with the "attempted to read or write protected memory error"

Is the dll import signature correct? Please throw some light on this. Thanks

Maithili

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