What's the type of vistatus-VISA programming

[yangyang-rexxar]

Hi All

My custom has a dll which is based on NI-VISA to control their own instrument, I need to import this win32 dll in C#.net,

the prototype of a method in dll is   "ViStatus TXPRMGR_errorMessage (ViSession instrumentHandle,ViStatus statusCode,ViChar _VI_FAR message[]);  "

In my C# code, I wrote down like this  [DllImport("Targetdll.dll")]
                                                                public static extern type(type1 instrumentHandle, type2 statusCode, type3 message[]);

Please mind the red part, I don't know what type I should write down.

I'm not familiar with visatype.

Thanks very much.

Bestwishes

Rexxar.Ben

[yangyang-rexxar]

Hi

My code as follow,but it does not work.

I am fresh with NI-VISA custom type.

  [DllImport("TXP_ResMgrDrv_32.dll")]
  public static extern Int32 TXPRMGR_errorMessage( Int32 instrumentHandle, Int32 statusCode, [MarshalAs(UnmanagedType.LPStr)] ref string message);

[bilalD]

This really has nothing to do with VISA, but try this (assuming stdcall calling convention)

[DllImport("TXP_ResMgrDrv_32.dll",CallingConvention=CallingConvention.StdCall)]
public static extern Int32 TXPRMGR_errorMessage (System.IntPtr Instrument_Handle, int Error_Code, System.Text.StringBuilder message);

If this doesnt work, you'll need to keep trying different configurations and make sure you understand how .NET handles interop.