gridview绑定，如果T1这一列中的某一行的值为15:00，则这一单元格不显示内容，为空
而其他T2、T3列绑定的数据能正常显示
[解决办法]
调整一点

string sqlstr = "select ID,booktime,DATENAME(weekday,booktime) as weekday ,T1 ,T2,T3 
from (select id,T1=case when T1='15:00' then null else T1 end ,T2,T3 datename(week,booktime)as week,booktime from [aspnetdb].[dbo].[book]) b 
where week=(select DATENAME(WEEK,getdate()))";