程序代码：

 private void frmStudent_Load(object sender, EventArgs e)
        {
            daClass.Fill(dsStudent.Class);
            daStudent.Fill(dsStudent.Student);
            CurrencyManager cmStudent;
            cmStudent = (CurrencyManager)this.BindingContext[dsStudent, "Student"];
        }
        private void DisPosition()
        {
            n = cmStudent.Positon + 1;
        }