DataGridView中DataGridViewComboBoxColumn无法赋值问题

给DataGridViewComboBoxColumn赋值时注意先保证下拉列表中存在数据，没有则会引发DataError异常。

//先保证下拉框有值

((DataGridViewComboBoxCell)this.dgv_Schedule.Rows[i].Cells["dTIME_DESC"]).DataSource = PublicClasses.TimeInterval;

((DataGridViewComboBoxCell)this.dgv_Schedule.Rows[i].Cells["dTIME_DESC"]).DisplayMember = "TIME_INTERVAL_NAME";

((DataGridViewComboBoxCell)this.dgv_Schedule.Rows[i].Cells["dTIME_DESC"]).ValueMember = "TIME_INTERVAL_CODE";

//后赋值

 this.dgv_Schedule.Rows[i].Cells["dTIME_DESC"].Value = table.Rows[i]["TIME_INTERVAL_CODE"].ToString();