I am having trouble with a binding that was created to format a textbox on a
form. I have created a format procedure that takes a date and makes a
string, so that it can be displayed as a short date.

Private Sub DatetoShort(ByVal sender As Object, ByVal cevent As
ConvertEventArgs)
' The method converts only to string type. Test this using the DesiredType.

If Not cevent.DesiredType Is GetType(String) Then

Exit Sub

End If

' Use the ToshortDate method to format short date

Try ' if date is null then catch

cevent.Value = CType(cevent.Value, Date).ToShortDateString

Catch

End Try

End Sub


The problem I have is that I can't figure out how to get the value to go to
null if the date needs to be erased. For example, a date of birth might not
be available. If it is not entered into the database with a new record then
there is no problem. But then if I change the value and give it a date. I
can't erase the date later. The code for the textbox is as follows:
' Create the binding date of birth

Dim bBirthdate As Binding = New Binding _

("Text", Me.objAlphaStudent, "DERecords.birthdate")

' Add the delegates to the event

AddHandler bBirthdate.Format, AddressOf DatetoShort

txtbDOB.DataBindings.Add(bBirthdate)

If I try to reset the textbox.text property to "" it just reverts back to
whatever date was entered and accepted. What can I do to erase the field
(set it to null) after a valid date has been entered?

Add a parse event handler, something like this:

Dim bBirthdate As Binding _
= New Binding ("Text", Me.objAlphaStudent, "DERecords.birthdate")

AddHandler bBirthdate.Format, AddressOf DatetoShort
txtbDOB.DataBindings.Add(bBirthdate)

Private Sub DatetoShort(ByVal sender As Object, _
ByVal cevent As ConvertEventArgs)

If cevent.Value = "" Then
cevent.Value = DBNull.Value
Else
cevent.Value = DateTime.Parse(cevent.Value)
End If

End Sub

Per-Frode Pedersen

"Michael Roberts Jr" <(E-Mail Removed)> wrote in message news:<zLlYa.249618$(E-Mail Removed)>...
> I am having trouble with a binding that was created to format a textbox on a
> form. I have created a format procedure that takes a date and makes a
> string, so that it can be displayed as a short date.
>
> Private Sub DatetoShort(ByVal sender As Object, ByVal cevent As
> ConvertEventArgs)
> ' The method converts only to string type. Test this using the DesiredType.
>
> If Not cevent.DesiredType Is GetType(String) Then
>
> Exit Sub
>
> End If
>
> ' Use the ToshortDate method to format short date
>
> Try ' if date is null then catch
>
> cevent.Value = CType(cevent.Value, Date).ToShortDateString
>
> Catch
>
> End Try
>
> End Sub
>
>
> The problem I have is that I can't figure out how to get the value to go to
> null if the date needs to be erased. For example, a date of birth might not
> be available. If it is not entered into the database with a new record then
> there is no problem. But then if I change the value and give it a date. I
> can't erase the date later. The code for the textbox is as follows:
> ' Create the binding date of birth
>
> Dim bBirthdate As Binding = New Binding _
>
> ("Text", Me.objAlphaStudent, "DERecords.birthdate")
>
> ' Add the delegates to the event
>
> AddHandler bBirthdate.Format, AddressOf DatetoShort
>
> txtbDOB.DataBindings.Add(bBirthdate)
>
> If I try to reset the textbox.text property to "" it just reverts back to
> whatever date was entered and accepted. What can I do to erase the field
> (set it to null) after a valid date has been entered?