Using system;using system.io;string filetomerge=@ "C:\temp\data.bin"; string targetpath=@ "D:\store"; string strFileName = Filetomerge. Substring (Filetomerge. LastIndexOf (Path.directoryseparatorchar) + 1); FileStream FSR1 = new FileStream (targetpath+ Path.directoryseparatorchar + strFileName + "1", FileMode.Open, FILEACCESS.R EAD); FileStream FSR2 = new FileStream (targetpath+ Path.directoryseparatorchar + strFileName + "2", FileMode.Open, FILEACCESS.R EAD); byte[] Btarr = new BYTE[FSR1. LENGTH+FSR2. LENGTH];FSR1. Read (Btarr, 0, Convert.ToInt32 (FSR1. Length)); FSR2. Read (Btarr, Convert.ToInt32 (FSR1. Length), Convert.ToInt32 (FSR2. Length)); fsr1. Close (); fsr2. Close (); FileStream FSW = new FileStream (%%2 + path.directoryseparatorchar+ strFileName, FileMode.Create, FileAccess.Write); fsw. Write (Btarr, 0, btarr.length); fsw. Flush (); fsw. Close ();