check if a textbox value already exists in a listbox

Question

I have a ListBox bound to a observableCollection of "widgets". Each widget in the collection only has a name field at the moment but that will change.

On the window I have a text box where a user can enter another name for addition to the observableCollection.

Each entry has to be unique.

At the moment I use this

  Dim query As IEnumerable(Of clsWidget)
  query = WidgetSource.Where(Function(widget) widget.name = txtNewName.Text)

  If query.Count > 0 Then
    Debug.Print("Tried to add a widget that already in the collection")
  End If

Is there a more efficient way of doing this?

Yes. But you wouldn't feel the difference in performance. Look at [this](http://stackoverflow.com/questions/305092/which-method-performs-better-any-vs-count-0) — Peuczynski, May 15 '16 at 13:34

score 0 · Accepted Answer · answered May 15 '16 at 13:59

It can be more efficiently coded by using the code below which only requires one line.

    If WidgetSource.Any(Function(widget) widget.name = txtNewName.Text) Then Debug.Print("Tried to add a widget that already in the collection")

If by efficient you mean it runs faster then I doubt there will be much difference between my code and yours.

check if a textbox value already exists in a listbox

1 Answers1