combobox event sequance question

Question

i have a combobox where when the user selects one of its options the option is removed from the second combobox
my code goes somthing like this:

    Private Sub Combo_DropDownClosed(sender As ComboBox, e As EventArgs) Handles dropdown1.???
                If dropdown1.Text = "" Then
                             dropdown2.Items.Remove(dropdown1.SelectedItem)
                ElseIf dropdown1.Text <> dropdown1.SelectedItem Then
                             dropdown2.Items.Add(dropdown1.Text)
                             dropdown2.Items.Remove(dropdown1.SelectedItem)
                End If
    end sub

what can i replace '???' with that happens before the text is written over(dropdown1.Text is still equal to "") and after a item is selected? (dropdown1.SelectedItem is equal to 'example 1' or somthing)

to be clear when the above code completes dropdown2 should not contain what the user selected

Answer 1

I created two combo boxes with string items in them. Then I tested this code and it worked.

    Private Sub ComboBox1_SelectedIndexChanged(sender As Object,
                                               e As EventArgs) Handles ComboBox1.SelectedIndexChanged

        For idx As Integer = 0 To ComboBox2.Items.Count - 1
            Dim itm As String = DirectCast(ComboBox2.Items(idx), String)
            If ComboBox1.SelectedItem Is itm Then
                ComboBox2.Items.RemoveAt(idx)
                Exit For
            End If
        Next
    End Sub

Answer 2

Hi
Dewayne beat me to it. However, here is my offering.

' Form1 with ComboBox1
' and ComboBox2
Option Strict On
Option Explicit On
Public Class Form1
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        ' sample data for ComboBoxes
        ComboBox1.Items.AddRange({"One", "Two", "Three", "Four", "Five"})

        ' same data just mixed a little
        ComboBox2.Items.AddRange({"Two", "Three", "Five", "One", "Four"})

    End Sub
    Private Sub ComboBox1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ComboBox1.SelectedIndexChanged
        Dim s As String = ComboBox1.SelectedItem.ToString
        Dim cb2ind As Integer = ComboBox2.FindString(s)
        If cb2ind > -1 Then
            If MessageBox.Show("Found " & s & " at index " & cb2ind.ToString & " in Combobox2" & vbCrLf & "Click YES to delete it.", "Delete item from CB2", MessageBoxButtons.YesNo) = DialogResult.Yes Then
                ComboBox2.Items.Remove(s)
            End If
        Else
            MessageBox.Show("'" & s & "' was not found in Combobox2")
        End If
    End Sub
End Class

Answer 3

Hi
Here is some info on finding and using auto handler insertion.

From the Designer, select a Control (ComboBox in your case), and then choose the lightning symbol (see image) from the Property pane - this will open all the events for the control. Double click on the event you wantto use and the base framework for the event will be inserted into your code.

Alternatively, when in the code editor, and say you have one Handler Sub there and you want to insert another for a different event, then put the cursor in the existing Handler code and choose the drop down above (see image) and select the desired event you want and the base code will be inserted into your code.

Doing thing that way will deal with the (signatures) needed to handle the event.

The 'signature' you want above is:

Private Sub ComboBox1_DropDownClosed(sender As Object, e As EventArgs) Handles ComboBox1.DropDownClosed  

Answer 4

after thoroughly inserting my code into every possibly event ive come to the conclusion that for some reason none of them are able to do what my code used to be able to do
there isnt an event that occurs before the text is updated, ill have to write my code around that fact now