[RESOLVED] VS 2012, How do I get the text contents from combobox, and put it into a ListBox

[darkchickenex1]

As the title says, how do I get the text contents from a combobox, and put it into a List Box. Thanks

[dday9]

If you want to get just the selected item:

Dim str As String = ComboBox1.SelectedItem.ToString
        ListBox1.Items.Add(str)

If you want to get all the items:

For i As Integer = 0 To ComboBox1.Items.Count - 1
            Dim str As String = ComboBox1.Items(i).ToString
            ListBox1.Items.Add(str)
        Next

Generally speaking we like to see an effort on your behalf first.

[darkchickenex1]

Thanks for the reply, but I'm getting "An unhandled exception of type 'System.InvalidOperationException' occured in WindowsApplication1.exe"

I am new to all this, so I do apologize.

[dday9]

A couple of questions, and don't get mad if I ask them, these are legit questions:

1. Do you have a listbox that's named "ListBox1"?
2. Do you have a combobox that's named "ComboBox1"?
3. What are you using to trigger that code I provided?

Could you also post the control you're using to trigger the code that I provided including any event handlers? Like for example, if you're using a button the event handlers would look something like this:

Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
 
    End Sub

The Handles Button1.Click is mainly what I'm looking for.

[darkchickenex1]

As I said I am new, but yeh I do have have a ListBox1 and ComboBox1

I am using the form itself to trigger it:

Public Class Form1
    Dim Str As String = ComboBox1.SelectedItem.ToString
    Private Sub ListBox1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ListBox1.SelectedIndexChanged
        ListBox1.Items.Add(Str)
    End Sub
End Class

I also tried using a button, but again it didn't load and gave me the same error

[dday9]

Ah, ok. What you'd want to do is put it into the form_load event. You have 3 ways of doing so:

1. Double-click anywhere on the form in the designer view
2. In the designer view:
   
   • Click any where on the form
   • Click the events. That's the ligtning bolt next to the form's properties
   • Double-click the load event
3. In the code view:
   
   • Click on the upper left combobox and choose "Form1 Events"
   • Click on the upper right combobox and choose "Load"

Either way to decide to use you should have this:

Private Sub Form1_Load(sender As Object, e As System.EventArgs) Handles Me.Load
 
    End Sub

The reason it isn't working right now is because there is no event that's triggering the code to perform.

[darkchickenex1]

I tried what you just said, and still nothing. Below is an image of the error message, maybe this will help?!



After this code:

Public Class Form1
    Dim Str As String = ComboBox1.SelectedItem.ToString

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        ListBox1.Items.Add(Str)
    End Sub
End Class

[dday9]

Ah, ok I see... I misread your post in post # 5. I would suggest still using the selectedindexchanged event(double click on the combobox), but it should look like this:

Option Strict On
Option Explicit On
Public Class Form1

    Private Sub ComboBox1_SelectedIndexChanged(sender As System.Object, e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged
        Dim str As String = ComboBox1.SelectedItem.ToString
        ListBox1.Items.Add(str)
    End Sub

End Class

The reason being is you want to set the variable str right before you add str to the listbox. Take a look at this MSDN article on variable levels.

[darkchickenex1]

Brilliant, it works, I really appreciate your help!

[dday9]

No problem, be sure that you mark the thread resolved under thread tools(At the top of this page).