Need help with changing label value depeding on two dropdown

So i want to change my label named total value depending on two dropdown lists i have written a code to try working with one dropdown list but the label value is not changing this is my code:

protected void DropDownPermit_SelectedIndexChanged(object sender, EventArgs e)
{
if (this.DropDownPermit.SelectedValue == "Blue")
{
this.total.Text = "$10.00";
}

can someone help me