String DbPath = System.Windows.Forms.Application.StartupPath+"\\AGMDB.mdf";
command = new SqlCommand(@"backup database "+ DbPath +" to disk ='d:\svBackUp1.bak' with init,stats=10",connect);
or use can use
command = new SqlCommand("backup DataBase "+DbPath +" to
disk = 'd:\svBackUp1.bak' with noformat, noinit, name = 'AGMDB',
skip,norewind,nounload,stats=10")