Store Viewstate in persistent medium or secondary medium

Viewstate is a very helpful thing in ASP.NET only if it is used properly.

Viewstate can be tampered and excess use of viewstate makes the page heavier.
You can disable Viewstate of the page or individual controls to make page lighter.
But in cases where you can't disable viewstate for any page or any control, or in places where the page is heavier after optimization also, you can store viewstate value in secondary memory.

To achieve that you need to override two methods
1. SavePageStateToPersistenceMedium
2. LoadPageStateFromPersistenceMedium

First method is used to save viewstate to secondary storage and second one is used to load viewstate value from secondary storage.

The following code describe what to do:

protected override void SavePageStateToPersistenceMedium(object state)
{
	FileStream objFileStream = new FileStream(@"D:\TempViewState.txt", FileMode.OpenOrCreate, FileAccess.Write);
	LosFormatter formatter = new LosFormatter();

	formatter.Serialize(objFileStream, state); // Serializes viewstate object and stores it in the file.
	objFileStream.Close(); // Closes the file to release the resource.

	return;
}

protected override object LoadPageStateFromPersistenceMedium()
{
	FileStream objFileStream = new FileStream(@"D:\TempViewState.txt", FileMode.Open, FileAccess.Read);
	StreamReader reader = new StreamReader(objFileStream);

	// Read the file content and closes the file.
	string state = reader.ReadToEnd();
	reader.Close();

	// Deserialize the file content.
	LosFormatter lof = new LosFormatter();
	return lof.Deserialize(state);
}