CODEWITHSUNDEEP
vb.netcombobox
BAE
BAE

Reputation: 8946

Why is ComboBox SelectedIndexChanged being called before form load?

why Private Sub combobox_SelectedIndexChanged(sender As Object, e As EventArgs) Handles combobox.SelectedIndexChanged called before form appears? In my understanding, this function should be called ONLY when user change the selected index of mycombobox? Am I wrong?

How to stop it from running automatically?

Upvotes: 1

Views: 2958

Answers (1)

Luc Morin
Luc Morin

Reputation: 5380

You could either use a Boolean flag indicating when it is "safe" to handle the event, or you could use the alternative syntax to add your event handler AFTER the Form is loaded and all the initialization has been done.

For this you use the AddHandler syntax:

AddHandler combobox.SelectedIndexChanged, AddressOf combobox_SelectedIndexChanged

Hope this helps

EDIT:

Using the AddHandler syntax, you must make sure NOT to add the Handles clause to your event handler declaration:

Private Sub combobox_SelectedIndexChanged(sender As Object, e As EventArgs) 
'you event handler code
End Sub

Then, typically at the end of the Form's OnLoad override, you'll use the AddHandler:

Public Class Form1

    Protected Overrides Sub OnLoad(e As EventArgs)
        MyBase.OnLoad(e)

        ' Initialization code/whatever

        AddHandler ComboBox1.SelectedIndexChanged, AddressOf combobox_SelectedIndexChanged

    End Sub

    Private Sub combobox_SelectedIndexChanged(sender As Object, e As EventArgs)
    'Your event handler code
    End Sub

End Class

Upvotes: 1

Related Questions