Microsoft Windows Communication Foundation 4.0 Cookbook for Developing SOA Applications

Returning ReadOnlyCollection data

It is quite common to return a collection of data objects in a WCF service operation. However, sometimes we need to return a list of objects that are stored in the ReadOnlyCollection<T> type instance. This cannot be done directly, since ReadOnlyCollection<T> is not supported by the WCF DataContractSerializer. To make a WCF service operation return an ReadOnlyCollection<T> collection, we need to perform some customization on the OperationContract.

How to do it...

To return ReadOnlyCollection<T> collection instances, we need to modify our WCF service operation's OperationContract—the return type should be changed to use a base/generic Collection type other than ReadOnlyCollection<T>. For example, in our sample service, ...