Asp Net Session State Serialization
Piet Obermeyer and Jonathan Hawkins Microsoft Corporation August 2001 Updated March 2002 Summary: Why would you want to use serialization? The two most important reasons are to persist the state of an object to a storage medium so an exact copy can be recreated at a later stage, and to send the object by value from one application domain to another.
The following are the client-side state management options that ASP.NET. You can manually serialize and de-serialize. ASP.NET provides a session state. Session State Providers Profile. Core ASP.NET session state services. The fundamental job of a session state provider is to serialize SessionStateDataStores to. Unable to serialize the session state using stateserver. Unable to serialize the session state. ASP.NET will serialize the session state objects.
For example, serialization is used to save session state in ASP.NET and to copy objects to the clipboard in Windows Forms. It is also used by remoting to pass objects by value from one application domain to another. This article provides an overview of the serialization used in the Microsoft.NET Framework. (9 printed pages) Contents Introduction Serialization can be defined as the process of storing the state of an object instance to a storage medium. During this process, the public and private fields of the object and the name of the class, including the assembly containing the class, is converted to a stream of bytes, which is then written to a data stream.
When the object is subsequently deserialized, an exact clone of the original object is created. When implementing a serialization mechanism in an object-oriented environment, you have to make a number of tradeoffs between ease of use and flexibility. The process can be automated to a large extent, provided you are given sufficient control over the process. For example, situations may arise where simple binary serialization is not sufficient, or there might be a specific reason to decide which fields in a class need to be serialized. The following sections examine the robust serialization mechanism provided with the.NET Framework and highlight a number of important features that allow you to customize the process to meet your needs.
Persistent Storage It is often necessary to store the value of fields of an object to disk and then retrieve this data at a later stage. Although this is easy to achieve without relying on serialization, this approach is often cumbersome and error prone, and becomes progressively more complex when you need to track a hierarchy of objects. Imagine writing a large business application containing many thousands of objects and having to write code to save and restore the fields and properties to and from disk for each object. Serialization provides a convenient mechanism for achieving this objective with minimal effort.
The Common Language Runtime (CLR) manages how objects are laid out in memory and the.NET Framework provides an automated serialization mechanism by using reflection. When an object is serialized, the name of the class, the assembly, and all the data members of the class instance are written to storage.
Objects often store references to other instances in member variables. When the class is serialized, the serialization engine keeps track of all referenced objects already serialized to ensure that the same object is not serialized more than once. The serialization architecture provided with the.NET Framework correctly handles object graphs and circular references automatically.
The only requirement placed on object graphs is that all objects referenced by the object that is being serialized must also be marked as Serializable (see ). If this is not done, an exception will be thrown when the serializer attempts to serialize the unmarked object. When the serialized class is deserialized, the class is recreated and the values of all the data members are automatically restored.
Marshal By Value Objects are only valid in the application domain where they are created. Any attempt to pass the object as a parameter or return it as a result will fail unless the object derives from MarshalByRefObject or is marked as Serializable. If the object is marked as Serializable, the object will automatically be serialized, transported from the one application domain to the other, and then deserialized to produce an exact copy of the object in the second application domain. This process is typically referred to as marshal by value. When an object derives from MarshalByRefObject, an object reference will be passed from one application domain to another, rather than the object itself. You can also mark an object that derives from MarshalByRefObject as Serializable. When this object is used with remoting, the formatter responsible for serialization, which has been preconfigured with a SurrogateSelector takes control of the serialization process and replaces all objects derived from MarshalByRefObject with a proxy.
Net Standard Serialization
Without the SurrogateSelector in place, the serialization architecture follows the standard serialization rules (see ) below. Basic Serialization The easiest way to make a class serializable is to mark it with the Serializable attribute as follows. MyObject obj = new MyObject; obj.n1 = 1; obj.n2 = 24; obj.str = 'Some String'; IFormatter formatter = new BinaryFormatter; Stream stream = new FileStream('MyFile.bin', FileMode.Create, FileAccess.Write, FileShare.None); formatter.Serialize(stream, obj); stream.Close; This example uses a binary formatter to do the serialization.
All you need to do is create an instance of the stream and the formatter you intend to use, and then call the Serialize method on the formatter. The stream and the object instance to serialize are provided as parameters to this call. Although this is not explicitly demonstrated in this example, all member variables of a class will be serialized, even variables marked as private. In this aspect, binary serialization differs from the XML Serializer, which only serializes public fields.
Restoring the object back to its former state is just as easy. First, create a formatter and a stream for reading, and then instruct the formatter to deserialize the object. The code snippet below shows how this is done. 1 24 Some String It is important to note that the Serializable attribute cannot be inherited.
If we derive a new class from MyObject, the new class must be marked with the attribute as well, or it cannot be serialized. For example, when you attempt to serialize an instance of the class below, you will get a SerializationException informing you that the MyStuff type is not marked as serializable.
Unable to serialize the session state. In ‘StateServer’ and ‘SQLServer’ mode, ASP.NET will serialize the session state objects, and as a result non-serializable objects or MarshalByRef objects are not permitted. The same restriction applies if similar serialization is done by the custom session state store in ‘Custom’ mode. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Asp Net Session Examples
Exception Details: System.Web.HttpException: Unable to serialize the session state. In ‘StateServer’ and ‘SQLServer’ mode, ASP.NET will serialize the session state objects, and as a result non-serializable objects or MarshalByRef objects are not permitted. The same restriction applies if similar serialization is done by the custom session state store in ‘Custom’ mode.
Source Error: An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. ASP.NET web application handles the storage of session objects differently from InProc mode to SQLServer mode. When storing session objects into a SQL Server,.NET framework will serialize the objects.
This is necessary because the session object needs to be transferred from server to server. Tip: You can get more tutorials on, and other here. Bonus – Error Indication Also note that this error can come from different reasons. Here are two other possible reasons that may or may not cause you unable to serialize error:. Check all the objects that you are using in that class, and remove the objects that are non-serializable. Also if you are using HttpResponse object then remove it from that class because that object is non-serializable and find out alternate method to pass response Note: You can also find the class that needs to be serializable by traversing the code or nested exceptions.
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