first place one textbox and combobox on the form. name them text1 and combo1 respectively.....


Private Sub Form_Load()
Combo1.Clear

Combo1.AddItem "AAA"
Combo1.AddItem "BBB"
Combo1.AddItem "CCC"
Combo1.AddItem "DDD"

End Sub

Private Sub Combo1_Click()
Text1.Text = Combo1.Text
End Sub


or u can try this



Private Sub text1_gotfocus()
If Combo1.Text = "" Then
MsgBox "Please select a value from the list first."
Combo1.SetFocus
Exit Sub
Else
Text1.Text = Combo1.Text
End If
End Sub


Private Sub Form_Load()
Combo1.Clear

Combo1.AddItem "AAA"
Combo1.AddItem "BBB"
Combo1.AddItem "CCC"
Combo1.AddItem "DDD"

End Sub