Set Value in TextBox On DropDownList Change depending on SelectedValue

i tried this code and it works fine

Protected Sub DropDownList1_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles DropDownList1.SelectedIndexChanged
        If DropDownList1.SelectedValue = "Dir" Then
            TextBox1.Text = 1
        End If
        If DropDownList1.SelectedValue = "Dy Dir" Then
            TextBox1.Text = 2
        End If
        If DropDownList1.SelectedValue = "SO" Then
            TextBox1.Text = 3
        End If
        If DropDownList1.SelectedValue = "HOD" Then
            TextBox1.Text = 4
        End If