Question

How does this code work?

      app.InstallStateChanged += (s, e) => UpdateUI();
      NetworkChange.NetworkAddressChanged +=
            (s, e) => UpdateNetworkIndicator();

Can someone please unscramble this?

The code comes from an example used in a silverlight 4 OOB systems http://msdn.microsoft.com/en-us/library/dd833066(v=VS.95).aspx

UpdateNetworkIndicator does not return anything.
UpdateUI does not return anything.

Answer 1

Both the UpdateUI() and UpdateNetworkIndicator() methods are custom event handler methods.

The += operator is attaching these event handlers to the events fired by the app and NetworkChange respectively.

The => denotes a lambda expression. The (s,e) are input parameters (in this case, the standard sender, event args) and the right of => is the statement or expression.

In this case, you could rewrite this as:

app.InstallStateChanged += UpdateUI;
NetworkChange.NetworkAddressChanged += UpdateNetworkIndicator;

and it should work just as well.