UI: Click event to button?

I have a form with a button on it - When the button is clicked, I want some code to run... How can I do this?

I've got this code so far (extract):

Dim oItem As SAPbouiCOM.Item

Dim oButton As SAPbouiCOM.Button

oItem = frmVareAddOn.Items.Add("Seek", SAPbouiCOM.BoFormItemTypes.it_BUTTON)

With oItem

.Height = 19

.Left = 365

.Top = 28

.Width = 65

End With

oButton = oItem.Specific

oButton.Caption = "Seek..."

How can I tell the application that a messagebox should be displayed, when the button is clicked?

Hope someone can help!