Web Service Software Factory

Excerpts from Web Service Software Factory: Modeling Edition

internal class StateData: IExtension<InstanceContext>
{
    public string Identifier = string.Empty;
    public string Data = string.Empty;
 
    public StateData( string data )
    {
        Identifier = Guid.NewGuid().ToString();
        Data = data;
    }
}
 
public string AddStateData( string data )
{
    StateData state = new StateData( data );
    OperationContext.Current.InstanceContext.Extensions.Add(state);
    return state.Identifier;
}
 
public string GetStateData( string identifier )
{
    Collection<StateData> dataCollection = 
        OperationContext.Current.InstanceContext.Extensions.FindAll<StateData>();
 
    string result = string.Empty;
    foreach( StateData data in dataCollection )
    {
        if( data.Identifier == identifier )
        {
            Result = data.Data;
            break;
        }
    }
    return result;
}

As discussed in Differences Between ASMX and WCF Services, some capabilities can be supported only when using the
 ASP.NET Compatibility mode. These capabilities include the following:
 
Security. With WCF, active control lists (ACLs) cannot be used to restrict access to the file system. In addition, WCF does 
not support the use of profiles introduced in ASP.NET 2.0. 
State management. WCF provides limited support for state management. Maintaining state in a Web service is not 
recommended, but you may be migrating an application that depends on state that is managed by the HttpContext object.