winform 往DataGridVie 中添加勾选框默认问题

  DataGridViewCheckBoxColumn newColumn = new DataGridViewCheckBoxColumn();
            newColumn.HeaderText = "不许空";
            newColumn.Name = "不许空";
            newColumn.TrueValue = true;
            newColumn.FalseValue = false;
            dataGridView1.Columns.Insert(2, newColumn);

我先添加一个勾选框
然后再数据库中查询默认值是多少 然后给value赋值,问题是没有效果,还是空的并不是勾选或者没有勾选的状态,请问这是为什么

                    if (ds.Tables[0].Rows[0]["ISNull"].ToString() == "允许为空")
                    {
                        this.dataGridView1.Rows[i].Cells["不许空"].Value = true;
                    }
                    else
                    {
                        this. dataGridView1.Rows[i].Cells["不许空"].Value =false;

                  }

数据更新后要刷新datagridview
https://blog.csdn.net/originaldream/article/details/8826214?spm=1001.2101.3001.6650.3&utm_medium=distribute.pc_relevant.none-task-blog-2%7Edefault%7ECTRLIST%7Edefault-3.no_search_link&depth_1-utm_source=distribute.pc_relevant.none-task-blog-2%7Edefault%7ECTRLIST%7Edefault-3.no_search_link&utm_relevant_index=6