Suggest Append Count in combobox (vb.net) - vb.net

Question

I'm searching for a way to count my remaining suggest appends in my combobox.
In my example I have a list of 7 items
When I start to type with the suggest append function, this list gets narrowed down. But I don't see any possibility to count these remaining appends.
What my main objective is, is that I do an action once I have only 1 suggest append remaining.
But I can only check on the selectedindex, which is in this case always -1, or my comboboxcount is still 7. I don't see a way to count the remaining suggest appends.
Any idea?

Answer 1

Supposing that your combobox listitems are of string type then this code will do that. First you should create a list of string with combobox items. Then on keyup event of combobox you should create the searchtext which you use to filter list then count. See code below (i have shown also searchtext just to see its value):
Dim lst As New List(Of String)
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
For Each it In ComboBox1.Items
lst.Add(it)
Next
End Sub
Private Sub ComboBox1_KeyUp(sender As Object, e As KeyEventArgs) Handles ComboBox1.KeyUp
Dim seltext = ComboBox1.SelectedText
Dim searchtext = ""
If seltext <> "" Then
searchtext = ComboBox1.Text.ToLower.Replace(seltext, "")
Else
searchtext = ComboBox1.Text.ToLower
End If
Label1.Text = lst.Where(Function(d) d.ToLower.StartsWith(searchtext)).Count & " - " & searchtext
End Sub
If your combobox listitems are of different object type then you have to populate list with text field of listitem.

Answer 2

I had the same basic idea as Shurki, except I didn't use a list or replace the selected text with a zero-length string.
I use the SelectionStart property of the ComboBox to get a substring from the ComboBox's Text property..
Public Class Form1
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles Me.Load
ComboBox1.Items.Add("Candy")
ComboBox1.Items.Add("Car")
ComboBox1.Items.Add("Crush")
ComboBox1.Items.Add("Canned")
ComboBox1.Items.Add("Can")
End Sub
Private Sub ComboBox1_KeyUp(sender As Object, e As KeyEventArgs) Handles ComboBox1.KeyUp
Dim query As IEnumerable(Of Object) =
From item As Object In ComboBox1.Items
Where item.ToString().ToUpper().StartsWith(ComboBox1.Text.Substring(0, ComboBox1.SelectionStart).ToUpper())
Select item
Debug.WriteLine("Number of items: " & query.Count())
End Sub
End Class