private void frmStudent_Load(object sender, EventArgs e)
        {
            try
            {
                ObjClose();
                string sqlStr;
                DataBase db = new DataBase();
                DataSet ds = new DataSet();
                sqlStr = "select * from tbl_Student";
                ds = db.GetDataFromDB(sqlStr);
                if (ds == null)
                {
                    MessageBox.Show("没有任何学生记录!");
                }
                else
                {
                    dgrdvStudent.DataSource = ds.Tables[0];
                    dgrdvStudent.Columns[0].HeaderText = "学号";
                    dgrdvStudent.Columns[1].HeaderText = "姓名";
                    dgrdvStudent.Columns[2].HeaderText = "性别";
                    dgrdvStudent.Columns[3].HeaderText = "年龄";
                    dgrdvStudent.Columns[4].HeaderText = "所在系";
                    dgrdvStudent_CurrentCellChanged(sender, e);
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }
这段代码是随教材书附赠的源代码里面的，运行到"学号"那一行就出错了。其他地方好像也有相同的问题。我检查了数据库，没有发现什么错误，各位哥哥姐姐帮忙了！

发现问题了，原来是DataGridView载入和变更的时候会触发事件CurrentCellChanged，行索引会出现异常（不能正常索引）
int n = this.dgrdvStudent.CurrentCell.RowIndex;
这句就出错了，原来如此。