Hi everyone,

I am trying to convert the follwoing code from c++ to c#

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c++ code
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typedef short (WINAPI* PAC_ADT_SET_FINGER_STATUS)(
     short FingerStatus,
 (unsigned char)* Image,
 unsigned long RowNumber,
 unsigned long ColumnNumber,
        (unsigned char)* ContinueFlag);

typedef short (WINAPI * PAC_ADT_SET_MESSAGE)(
     int MessageID,
 (unsigned char)* ContinueFlag);

typedef short (WINAPI * PAC_ADT_SET_ADT_STATUS)(
     unsigned char StatusID,
 (unsigned char)* ContinueFlag);

typedef struct _AC_ADT_GUI_CALLBACK
{
   PAC_ADT_SET_FINGER_STATUS AC_ADT_SetFingerStatus;
   PAC_ADT_SET_MESSAGE       AC_ADT_SetMessages;
   PAC_ADT_SET_ADT_STATUS    AC_ADT_SetADTStatus;
} AC_ADT_GUI_CALLBACK, *PAC_ADT_GUI_CALLBACK;

short ADTSPIAPI AC_ADT_SetGUICallbacks(AC_ADT_GUI_CALLBACK
GUICallbackFunction);

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=====================================================================
#c code
---------------------------------------------------------------------

public delegate short PAC_ADT_SET_FINGER_STATUS(
  short FingerStatus,
  IntPtr Image,
  uint RowNumber,
  uint ColumnNumber,
  out byte ContinueFlag);

public delegate short PAC_ADT_SET_MESSAGE(
  int MessageID,
  out byte ContinueFlag);

public delegate short PAC_ADT_SET_ADT_STATUS(
  byte StatusID,
  out byte ContinueFlag);

[StructLayout(LayoutKind.Sequential)]
public class TAC_ADT_GUI_CALLBACK
{
[MarshalAs(UnmanagedType.FunctionPtr)]
public PAC_ADT_SET_FINGER_STATUS AC_ADT_SetFingerStatus;
[MarshalAs(UnmanagedType.FunctionPtr)]
public PAC_ADT_SET_MESSAGE AC_ADT_SetMessages;
[MarshalAs(UnmanagedType.FunctionPtr)]
public PAC_ADT_SET_ADT_STATUS AC_ADT_SetADTStatus;
}

public static extern short AC_ADT_SetGUICallbacks(TAC_ADT_GUI_CALLBACK
GUICallbackFunction);

=====================================================================

everytime I call the function it is comming back with "object instance not
set" exception.

Help will be appretiated

Fitim Skenderi