title: how to get this config value from app.config?
body: <p>My friend has the following app.config. He wants to get the value of <code>address</code>. how to do it?</p>
  
  <pre><code>&lt;configuration&gt;
      &lt;system.serviceModel&gt;
  ...
             &lt;client&gt;
              &lt;endpoint address="http://ldo:8080/LLService" binding="wsHttpBinding"
                  bindingConfiguration="WSHttpBinding_ILLService" contract="LLServiceReference.ILLService"
                  name="WSHttpBinding_ILLService"&gt;
                  &lt;identity&gt;
                      &lt;userPrincipalName value="ggldoe@mail.com" /&gt;
                  &lt;/identity&gt;
              &lt;/endpoint&gt;
          &lt;/client&gt;
      &lt;/system.serviceModel&gt;
  ...
  &lt;/configuration&gt;
  </code></pre>