Null Date in VB.NET 2005 Gridview

[jonbatts]

OK, I've got a Gridview that contains Users and their info; FirstName, LastName, .... It also contains "Last Login", a date. When "Last Login" is null, "1/1/0001 12:00:00 AM" is showing up. I understand that this is happening because a VB date can never really be "Nothing", but is instead set to "1/1/0001 12:00:00 AM". Typically I would just pass a string instead of a date, but I'm using a data layer with a "UserCollection" class like so.

Dim users As New UserCollection()
users.GetUsers()
grdUsers.DataSource = users
grdUsers.DataBind()

Any thoughts? Thanks, and have a great day.

 

[randysmid]

Hi,
If you are using SQL Server 2005, you'll have another "gotcha", because 01/01/0001 is invalid in SQL Server 2005. In SQL Server 2005, the minimum valid date value is 01/01/1753.

Don't ask me why, I'm just the messenger!!!

In any event, I'm using a initialized date of 01/01/1900. When I'm checking to see if someone entered a valid date, such as 4/27/2007, I'd first check to see if the value is 01/01/1900.

HTH, Randy

 

[blar9]

Just go to your query if it is for example

Select theDate from SomeTable

change to:

Select IsNull(theDate,'') from SomeTable

then you wont have to change your code and it will give you a null value from the query.

 

[jonbatts]

As I mentioned, it not as simple as changing a query because I'm using a datalayer of which the property for "LastLogin" is a date. Thus, in VB, A Date must be a date. Not an empty string, and not null ("Nothing"). I do appreciate your time and thoughts though.
One thing I thought about was adding a property to my User Object "LastLoginAsString", but to me that seems REALLY sloppy. Any other ideas?

 

[blar9]

You could check the value on databind like this:

Protected Sub GridView1_RowDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewRowEventArgs) Handles GridView1.RowDataBound
'Here you can change the value that gets displayed ie if it is '1/1/1900'
e.Row.Cells(0).Text
End Sub

 

[jonbatts]

While I wish there was a better way than having to check each row on RowDataBound, it will suffice. However, is there a more efficient way to check the cell that I want than referencing it by index. For instance, is there a "FindCellByName"? I hate to use index numbers to cells, because then i have to change the index number if I change the columns in the table. Thanks again, and have a great night.

 

[ca8msm]

You could create a nullable type for your date in your class. I believe jmeckley showed how to do this in a recent thread.


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