With Web Client Software Factory, when you require your application to store information in the session state, you can use the Composite Web Application Block class StateValue to store the information. This class supports code that runs both in a Web server environment (the session is available, and data is stored there) and outside of a Web server environment (no session is available, such as when you run your unit tests, and the data is stored in memory). Therefore, StateValue objects are useful to increase the testing surface of your application.
By default, StateValue objects use the ASP.NET Session when the code is running in a Web server. However, when persisting session information in ASP.NET web applications, developers may not want to rely on the ASP.NET Session state and might prefer to use their own persistence mechanism that, for example, uses a custom database.
The purpose of this post is to demonstrate how to create a new Session State Locator Service, and wire everything up so the StateValue injection occurs with your custom state persistence mechanism.
Implementation
1) Create a class that implements the IHttpSessionState interface. In this example, the session information is stored in a database.
public class MySessionState : IHttpSessionState
{
private DatabaseHelper _dbHelper;
private string _userName;
public MySessionState()
{
_dbHelper = new DatabaseHelper(/* connection string */);
_userName = HttpContext.Current.User.Identity.Name;
}
#region IHttpSessionState Members
public object this[string name]
{
get { return dbHelper.GetValue(_userName, name); }
set { dbHelper.SetValue(_userName, name, value); }
}
/// …
/// Our IHttpSessionState implementation
/// …
#endregion
}
2) Create a class that implements the Microsoft.Practices.CompositeWeb.Interfaces.ISessionStateLocatorService interface. This service must return an instance of the class that you implemented in the previous step. The Composite Web Application Block uses this service to inject an instance of IHttpSessionState to StateValue objects.
public class MySessionStateLocatorService : ISessionStateLocatorService
{
#region ISessionStateLocatorService Members
public System.Web.SessionState.IHttpSessionState GetSessionState()
{
return new MySessionState();
}
#endregion
}
3) Create a class that inherits from WebClientApplication class. In this class you will register your custom ISessionStateLocatorService.
public class MyWebApplication : WebClientApplication
{
}
4) Override the AddRequiredServices method, and add code that removes the SessionStateLocatorService service and registers the custom one.
public class MyWebApplication : WebClientApplication
{
protected override void AddRequiredServices()
{
base.AddRequiredServices();
base.RootContainer.Services.Remove();
this.RootContainer.Services.AddNew();
}
}
Using the Custom Implementation
To use the custom implementation you have to update the Global.asax file to specify the custom global application class.
<%@ Application Language=“C#” Inherits=“MyCustomSessionState.MyWebApplication” %>
After that, you can use StateValue objects to manage state across requests in the same way as always:
1) Add a public field of type StateValue to your class, where T is the type of the object you want to persist across requests (in this case, the Customer class)
public StateValue _currentCustomer;
2) To access the info, use the Value property of the StateValue class.
// Set the value
_currentCustomer.Value = new Customer();
// Get the value
Customer customer = _currentCustomer.Value;
You can find more information about the StateValue class in the topic Developing Web Client Applications | How to: Use Session State with Unit Testing from the WCSF Documentation.
Important: The code available for download is provided “as is” with no warranties of any kind.
Attachment(s): MyCustomSessionState.zip
