how can i check if an item is selected or not in a listbox?

[ethicalhacker]

Im using

Dim a As String = ListBox1.SelectedItem

to get the selected item on click of a button. I want to make sure that there is no error if the user clicks on the button without selecting an item, he should get a message "first select an item". Is there any kind of try catch exception I can use?

 

[JohnH]

Check first that the item IsNot Nothing.

 

[jmcilhinney]

How about not enabling the Button if an item isn't selected? Prevention is better than cure.

 

[ethicalhacker]

nice idea thanks, anymore solutions any more ways maybe using a try catch statement?

 

[Solitaire]

Verify that item in listbox is selected

Very simple:

If ListBox1.SelectedIndex > 0 Then
' do something with item at selected index
Else
MessageBox.Show("Please select an item from the list and try again.")
End If

 

[jmcilhinney]

In order to implement my suggestion set the Enabled property of the Button False in the designer. Handle the SelectedIndexChanged event of the ListBox and do this:

myButton.Enabled = (myListBox.SelectedIndex <> -1)