Question

i have a textbox bound to a datetime column in a dataset, but i cant set it to null or blank

Asked by: jltoops

here is the code
can anybody get this to work to set that datetime column back to DBNULL ????
(i have visual studio 2003)

   Dim b As New Binding("Text", ds, "XclMasterTable.endDate")
   AddHandler b.Format, AddressOf DateToString
   tb.DataBindings.Add(b)


    Private Sub DateToString(ByVal sender As Object, ByVal cevent As ConvertEventArgs)
        If Not (IsDBNull(cevent.Value)) Then
            cevent.Value = CType(cevent.Value, Date).ToShortDateString()
            'ToString("MM/dd/yy")
        Else
            cevent.Value = ""
            'Console.WriteLine("NOTHIGN DETECT5ED")
        End If
   
    End Sub

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Asked On
2006-03-09 at 06:27:50ID21767010
Tags

datetime

,

textbox

,

dataset

,

column

Topic

Microsoft Visual Basic.Net

Participating Experts
2
Points
500
Comments
3

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Answers

 

by: SanclerPosted on 2006-03-09 at 07:27:36ID: 16145379

Something like this (not tested, by the way)


   Dim b As New Binding("Text", ds, "XclMasterTable.endDate")
   AddHandler b.Format, AddressOf DateToString
   AddHandler b.Parse, AddressOf StringToDate '<<< NEW LINE
   tb.DataBindings.Add(b)


    Private Sub DateToString(ByVal sender As Object, ByVal cevent As ConvertEventArgs)
        If Not (IsDBNull(cevent.Value)) Then
            cevent.Value = CType(cevent.Value, Date).ToShortDateString()
            'ToString("MM/dd/yy")
        Else
            cevent.Value = ""
            'Console.WriteLine("NOTHIGN DETECT5ED")
        End If
   
    End Sub

    Private Sub StringToDate(ByVal sender As Object, ByVal cevent As ConvertEventArgs)

        If IsDate(cevent.Value)) Then
            cevent.Value = CType(cevent.Value, DateTime)
        Else
            cevent.Value = DBNull
        End If
   
    End Sub

Roger

 

by: jeretePosted on 2006-03-09 at 07:41:19ID: 16145538

This DBNull class differentiates between a null value (a null object) and an uninitialized value (the DBNull.Value instance) so I don't think you can actually uninitialize the value after it's been initialized.

 

by: jltoopsPosted on 2006-03-09 at 07:55:56ID: 16145717

   Private Sub DateToString(ByVal sender As Object, ByVal cevent As ConvertEventArgs)
        If Not (IsDBNull(cevent.Value)) Then
            cevent.Value = CType(cevent.Value, Date).ToShortDateString()
            'ToString("MM/dd/yy")
        Else
            cevent.Value = DBNull.Value
            'Console.WriteLine("NOTHIGN DETECT5ED")
        End If

    End Sub
    Private Sub StringToDate(ByVal sender As Object, ByVal cevent As ConvertEventArgs)

        If IsDate(cevent.Value) Then
            cevent.Value = CType(cevent.Value, DateTime)
        Else
            cevent.Value = DBNull.Value
        End If

    End Sub

OMG that worked .
I Have done somthing very 3 seperate times....
Thanks a lot!!!

20120131-EE-VQP-002

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