code listbox cộng trừ nhân chia

Private Sub Command1_Click()
If list1llistindex = 0 Then Text3.Text = Val(Text1.Text) + Val(Text2.Text)
If list1llistindex = 1 Then Text3.Text = Val(Text1.Text) - Val(Text2.Text)
If list1llistindex = 2 Then Text3.Text = Val(Text1.Text) * Val(Text2.Text)
If list1llistindex = 3 Then Text3.Text = Val(Text1.Text) / Val(Text2.Text)
If list1llistindex = 4 Then Text3.Text = Val(Text1.Text) Mod Val(Text2.Text)


End Sub

Private Sub Command2_Click()
Text1.Text = " "
Text2.Text = " "
Text3.Text = " "
End Sub

Private Sub Form_Load()
List1.AddItem "+", 0
List1.AddItem "-", 1
List1.AddItem "*", 2
List1.AddItem "/", 3
List1.AddItem "Mod", 4
End Sub