请教GRID表格列中加入了复选框,但不可修改值

如图所示,我在GRID表格中加入了复选框并且绑定了字段,目的是想通过点击复选框变更字段值。
请教在GRID设置了AllowCellSelection = .F. 的情况下,如何令复选框可用?谢谢!
我还特意看了一遍张洪举老师书上关于表格内加入列表框的例子,运行后发现一样不可选,好像被锁了一样
PROCEDURE oPlayList.Init WITH This .ReadOnly = .T. .DeleteMark = .F. .RecordMark = .F. .GridLines = 0 .ScrollBars = 0 .HighlightStyle = 2 .RecordSourceType = 1 .RecordSource = "songs" .ColumnCount = 2 WITH .Columns(1) WITH .Header1 .Caption = "歌星" .FontBold = .T. .Alignment = 2 ENDWITH .ControlSource = "songs.artiste" .Width = 60 ENDWITH WITH .Columns(2) WITH .Header1 .Caption = "曲目" .FontBold = .T. .Alignment = 2 ENDWITH .ControlSource = "JUSTSTEM(songs.song)" && 取songs表字段song的一部分,JUSTSTEM()函数是提取文件名字符串中扩展名前面的串,注意双引号! .Width = 120 ENDWITH ENDWITH ENDPROC