How to work with Callback function

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Dear all,
I need to invoke the callback function defined in the dll(build in c/c++) to the c#.net/vb.net application.I want the code and methodology to do it.
I really don't know how to do it with the callback functions.
I referred in net and found that it is need to use delegates for this purpose.
How to do it ? can any one explain me in detail about this ?
The following is the definition

C++

/* Callback function type */
typedef BOOL (CALLBACK* FUNCSCANBACK)(HGLOBAL hBuf, UINT unLines);

/*Function call*/
WORD WINAPI readdevice(WORD Lines,FUNCSCANBACK funcScanBack)

funcScanBack - callback function address. Reference to "FUNCSCANBACK" definition:
hBuf - Image buffer handle for callback.
unLines - Image lines in the buffer.

Return TRUE means continue read job, FALSE means cancel read job.

Posted 14-Nov-11 19:00pm

Ajaykumar.thurai

Updated 14-Nov-11 22:14pm

Mehdi Gholam

v2

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dieforwhat · Accepted Answer · 2011-11-15T03:16:00

C#

public delegate UNKNWON FUNCSCANBACK(IntPtr hBuf,UInt32 unLines);
public class yourClass{

[DllImport("yourdll")]
   public static extern UInt16 readdevice(UInt16 Lines, FUNCSCANBACK y);

void invokeFunc(){

readdevice(0,new FUNCSCANBACK(myCallBackFunc));

}

UNKNOWN myCallBackFunc(IntPtr hBuf,UInt32 unLines){




}
}

I used UNKNOWN as return type since I have no idea about CALLBACK*?