June 20, 2006 at 7:01 am
I have a date/time field in SQL Server 2000. My dot net app has a data grid where user can enter an appointment time.
I want to let user edit or even delete the time. If the user deletes the time, how can I save "Null" to the database in dot net.
Thank you,
June 21, 2006 at 8:20 am
Two things you need, first the column has to be defined nullable in the database. Then you can save System.DBNull when you update the table.
June 21, 2006 at 11:44 am
I have the column defined as nullable. I tried the following:
dr.appt_time = System.DBNull.Value
and get intellisense msg -- Value of type System.DBNull cannot be converted to date.
dr.appt_time = System.DBNull gives me the msg:
DBNull is a type in System and cannot be used as an expression.
I am trying to update via a dataset in a web app.
This shouldn't be that hard!!! Any other suggestions?
June 21, 2006 at 2:47 pm
put an explicit cast on the assignment
dr.appt_time = (datetime) System.DBNull.Value
June 22, 2006 at 12:23 am
Hello...
You might take a look at the so called "SmartDate" Datatype. This Datatype is NOT is default .NEt Datatype, but it is included with CSLA.Net from Rocky Lhotka. Its a datatype that will allow easier handling of NULLs in text fields ect. (Since it will accept blank strings and not blow up, also you can define if "NULL" means min or max date for comparisons) Try to look it up...I found it very handy. And there is also a "smartDatareader" which will strip away your NULLs since most times they are not "needed"
June 22, 2006 at 12:34 pm
I tried this
dr.appt_time = DirectCast(System.DBNull.Value, DateTime)
and got error: Invalid cast exception
What am I doing wrong here?
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