Winforms ListBox Control Not Updating After Source Changes

Question

I have a ListBox (LB) with a DataTable (DT) DataSource in the Form Class globally populated in the Form_Load event.

Private Sub frmEditPresets_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
    DT.Columns.Add("DisplayText")
    DT.Columns.Add("PresetID")
    For Each TSI As ToolStripItem In Presets.DropDownItems
        If TSI.Name.IndexOf("preset_") > -1 Then
            DT.Rows.Add(TSI.Text, TSI.Name)
        End If
    Next
    LB.DataSource = DT
    LB.DisplayMember = "DisplayText"
End Sub

When I use my Rename button. It updates the menu item and the Data Source but the Listbox doesn't refresh until I click another item in the listbox.

Rename code:

Private Sub btnRename_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnRename.Click
    Dim R As DataRowView = LB.SelectedItem
    Dim S As String = InputBox("Preset Name", "Rename", R("DisplayText"))
    If S.Trim.Length = 0 Then Exit Sub
    If Presets.DropDownItems.ContainsKey(R("PresetID").ToString) Then
        Presets.DropDownItems(R("PresetID").ToString).Text = S
    End If
    R("DisplayText") = S
End Sub

I'm sure this is a simple question with a simple answer but I can't seem to figure it out. I've tried Refresh(). I've tried setting the DataSource again. I read this StackOverflow question Winforms listbox not updating when bound data changes but ResetBindings() doesn't seem to be an available method in this context.

*Edit. I gave Steve credit for the answer as he mentioned BindingContext. Although, that led me to find BindingContext(DT).EndCurrentEdit() which updated my LB display and maintained the selection.

Many controls can't know when something inside an object has change. If I have a BindingList of `Foo`, it may know if I add/remove a `Foo`, but it doesn't know if `Foo.Property` has changed. To communicate those changes, `Foo` would need to implement INotifyPropertyChanged. Something similar might be at work here. — Jeff B, Jun 29 '12 at 17:49

Steve · Accepted Answer · 2012-06-29T18:11:33.677

1

Tried with this, and it works.....

Private Sub btnRename_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnRename.Click  
    Dim R As DataRowView = LB.SelectedItem  
    Dim S As String = InputBox("Preset Name", "Rename", R("DisplayText"))  
    If S.Trim.Length = 0 Then Exit Sub  
    If Presets.DropDownItems.ContainsKey(R("PresetID").ToString) Then  
        Presets.DropDownItems(R("PresetID").ToString).Text = S  
    End If  
    R("DisplayText") = S  
    BindingContext(DT).EndCurrentEdit()
End Sub

edited Jun 29 '12 at 18:11

answered Jun 29 '12 at 17:56

Steve

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Ooh.. BindingContext(DT).EndCurrentEdit() updated my Display and didn't unselect the item :D – DontFretBrett Jun 29 '12 at 18:02
Fine, the EndCurrentEdit is better. For the benefit of future readers of this question, I will update my answer with your suggestion.... – Steve Jun 29 '12 at 18:11
I dont understand. Where did you get DT? – PsychoData Dec 13 '13 at 20:19
@PsychoData It is a class level DataTable variable. See the first lines of question – Steve Dec 13 '13 at 20:21

Winforms ListBox Control Not Updating After Source Changes

1 Answers1