add data to commandColomn in datagridview

 GridViewTextBoxColumn txtColumnDay = new GridViewTextBoxColumn();
txtColumnDay.Name = "Days";
txtColumnDay.FieldName = "monthdays";
txtColumnDay.HeaderText = "monthdays";
txtColumnDay.Width = 60;
txtColumnDay.TextAlignment = ContentAlignment.MiddleCenter;
txtColumnDay.AutoSizeMode = BestFitColumnMode.None;
 dataGridView1.MasterTemplate.Columns.Add(txtColumnDay);

 GridViewMaskBoxColumn maskBoxColumnDay = new GridViewMaskBoxColumn();
 maskBoxColumnDay.Name = "Time";
 maskBoxColumnDay.FieldName = "UnitTime";
 maskBoxColumnDay.HeaderText = "Time";
 maskBoxColumnDay.MaskType = MaskType.Standard;
 maskBoxColumnDay.Mask = "00:00";
 maskBoxColumnDay.TextAlignment = ContentAlignment.BottomRight;
 maskBoxColumnDay.FormatString = "{00:00}";
 maskBoxColumnDay.DataType = typeof(TimeSpan);
 maskBoxColumnDay.Width = 60;
 maskBoxColumnDay.TextAlignment = ContentAlignment.MiddleCenter;
 maskBoxColumnDay.AutoSizeMode = BestFitColumnMode.None;
 dataGridView1.MasterTemplate.Columns.Add(maskBoxColumnDay);

DataTable dt = new DataTable();

 dt.Columns.Add("monthdays");
 dt.Columns.Add("UnitTime");
 dt.Rows.Add("monday","00:44");
 dt.Rows.Add("monday","20:44");
 dataGridView1.DataSource = dt;