ComboBox Question

Filespit · February 13th, 2011, 10:08 AM

Hi!

I am working on an application and need some help with comboboxes. In my form I have three comboboxes. When I select something in the first combobox, I want certain values to be added to the second combobox. Now, if I select one of the loaded values in the second combobox, I want certain values to be added to the third combobox. I have tried using both If-else and Cases, but nothing seems to work. Here's an example of my problem;

When I start the program, various music genres are loaded into ComboBox1.

Code:

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    ListGenre()
    ListArtist()
    ListAlbum()
End Sub

Public Sub ListGenre()
    ComboBox1.Items.Add("Rock")
    ComboBox1.Items.Add("Punk")
End Sub

If I select for example "Rock", I want ComboBox2 to load these values;

Code:

Public Sub ListArtist()
    Select Case ComboBox1.SelectedIndex
        Case "Rock"
            ComboBox2.Items.Add("Band1")
            ComboBox2.Items.Add("Band2")
    End Select
End Sub

And once i select one of the values in ComboBox2, I want ComboBox3 to load these values;

Code:

Public Sub ListAlbum()
    Select Case ComboBox2.SelectedIndex
        Case "Band1"
            ComboBox3.Items.Add("Album1")
            ComboBox3.Items.Add("Album2")
    End Select
End Sub

I hope I made myself somewhat understandable. Is this possible in some way? I'm obviously not doing right, so help would be much appreciated!

Apocolypse2005 · February 13th, 2011, 01:58 PM

For starters you've got a type mis match!

Code:

Select Case ComboBox1.SelectedIndex
        Case "Rock"
End Select

'That should be

Select Case ComboBox1.SelectedText
        Case "Rock"
End Select

'Or to be less ambiguous

Select Case ComboBox1.SelectedIndex
        Case 0
End Select

That should get you on ur way.

Also instead of testing for the selection in a seperate sub routine you can do it on the SelectedIndexChange event of each combobox which will make everything bit smoother!

Filespit · February 13th, 2011, 03:42 PM

Works perfectly, thank you.

However, if I select "Rock" in combobox1, and then select "Punk" in the same without selecting something in combobox2, "Band1" and "Band2" are added to combobox2 from "Rock", but "BandA" and "BandB" are also added to combobox2 from "Punk". How do I prevent this?

I only want "Band1" and "Band2" to be visible in combobox2 once I have selected "Rock" in combobox1, and "BandA" and "BandB" to be visible when I select "Punk".

Apocolypse2005 · February 13th, 2011, 04:44 PM

You need to clear the combo box each time then, so at the start or your event you need to state

Code:

comboBox1.Items.Clear

And depending how much you gotta clear and edit it might be worthwhile sticking in a

Code:

comboBox1.BeginUpdate
comboBox1.Items.Clear
comboBox1.EndUpdate

Same goes with adding to them!