BSTR type in c#

BSTR type in c#

• Ftan

  Change --> public static extern string

  into

  public static extern IntPtr

  and use the Marshal.PtrToStringBSTR to copy the BSTR to a managed string.

   

  Willy.

   

  <jan_hk@discussions.microsoft.com> wrote in message news:09e0537d-6ea0-49bf-a07b-3477eb7f2632@discussions.microsoft.com...

  I received a DLL which uses BSTR as string type:
  
  example : given in the include file
  

  DLLEXPORT BSTR WINAPI I2cGetInterfaceTypeStr (BSTR Interface);
  
  how do i access this function in vc#. This doesn't work.
  
  [DllImport("I2CAPI32.dll")] public static extern string I2cGetInterfaceTypeStr (string Interface);

  Other functions of the DLL which don't use BSTR are working ok.
  
  Can anyone help me.
  
  Thanks, Jan

   

   

  
  

• Khadragy

  There is something about BSTR on this link:
  http://msdn.microsoft.com/library/default.asp url=/library/en-us/csref/html/vcwlkCOMInteropPart1CClientTutorial.asp
  
  This might help you a little further on finding how to use what your are trying to do :)
  
  
  

• Martin Bussieres

  It's pretty unusual to see a function directly returning a BSTR like that, but I think this should work:
  

  [DllImport("I2CAPI32.dll", CharSet=CharSet.Unicode)] [return: MarshalAs(UnmanagedType.BStr)] public static extern string I2cGetInterfaceTypeStr([MarshalAs(UnmanagedType.BStr)] string Interface);

  
  
• BSTR type in c#