hi,
you are using wrong way for insert statement
use it like..
SqlCommand com = new SqlCommand("insert into txfile(mem_id,reg_id) values(@C1, @C2)", con);
com.Parameters.AddWithValue("@C1", v_mem_id);
com.Parameters.AddWithValue("@C2", v_reg_id);
con.Open();
com.ExecuteNonQuery();
con.Close();