Combo Box Drop down list to change a variable

Question

I am creating a program with a Drop Down-list combo Box which contain the items: a,b,cand d.

What I want to do is, when I select an item in the ComboBox and then click a button, the x variable will change. For example when I select b in the ComboBox, the x value will change to 2.

I need this variable for another function. How can I change the x variable?

[Set DisplayMember and ValueMember on ComboBox](http://stackoverflow.com/q/38206678/1070452) — Ňɏssa Pøngjǣrdenlarp, Jul 12 '16 at 16:11

score 2 · Accepted Answer · edited Jul 12 '16 at 13:53

2

If ComboBox1.SelectedItem.ToString = "a" Then
    x = 1
ElseIf ComboBox1.SelectedItem.ToString = "b" Then
    x = 2
ElseIf ComboBox1.SelectedItem.ToString = "c" Then
    x = 3
ElseIf ComboBox1.SelectedItem.ToString = "d" Then
    x = 4
End If

Assuming x is an Integer

edited Jul 12 '16 at 13:53

Visual Vincent

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answered Jul 12 '16 at 13:37

BanForFun

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thank you , currently im using `ComboBox.SelectedIndex` and it solve my problem, what the difference with `ComboBox1.SelectedItem` by the way? – Yon Jul 13 '16 at 14:42
@Yon - Selected index gets the position of the selected item. Ex. `0` (First) or `1` (Second) or `2` (Third) e.t.c. Selected item gets the text of the selected item (In your case: `a` or `b` or `c` or `d` e.t.c) – BanForFun Jul 13 '16 at 15:01
@Yon - Mark an answer so people know that you solved your problem. – BanForFun Jul 13 '16 at 15:11

score 2 · Answer 2 · answered Jul 12 '16 at 14:35

2

Or you could use a Select Case statement

Select Case ComboBox1.Text
    Case "a"
        x = 1 
    Case "b"
        x = 2
    Case "c"
        x = 3
    Case "d"
        x = 4
End Select

answered Jul 12 '16 at 14:35

Cal-cium

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i have solved the problem, thank you for the response – Yon Jul 13 '16 at 14:43

score 0 · Answer 3 · answered Jul 13 '16 at 15:00

The best way is to bind a datasource to your combobox. That way if you decide to add a new value later or change how it works, this is all in one place:

    Dim dict As New Dictionary(Of String, Integer)
    dict.Add("a", 1)
    dict.Add("b", 2)
    dict.Add("c", 3)
    dict.Add("d", 4)
    ComboBox1.DisplayMember = "Key"
    ComboBox1.ValueMember = "Value"
    ComboBox1.DataSource = New BindingSource(dict, Nothing)

then in the SelectedValueChanged Event you can read the value of x:

Private Sub ComboBox1_SelectedValueChanged(sender As Object, e As EventArgs) Handles ComboBox1.SelectedValueChanged
    If ComboBox1.SelectedValue IsNot Nothing Then x = CInt(ComboBox1.SelectedValue)
End Sub

Combo Box Drop down list to change a variable

3 Answers3