[silverlight]

الكود سيكون شئ من هذا القبيل

كود :

Public Class Form1



   Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
       ComboBox1.Items.Add("Any iteme 01")
       ComboBox1.Items.Add("Any iteme 02")
       ComboBox2.Visible = False
       ComboBox3.Visible = False
       ComboBox4.Visible = False

   End Sub

   Private Sub ComboBox1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ComboBox1.SelectedIndexChanged
       ComboBox2.Visible = True

   End Sub

   Private Sub ComboBox3_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ComboBox3.SelectedIndexChanged
       ComboBox3.Visible = True
   End Sub

   Private Sub ComboBox4_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ComboBox4.SelectedIndexChanged
       ComboBox4.Visible = True
   End Sub

End Class