View State

Each control on a Web Forms page, including the page itself, has a ViewState property, it is a built-in struture for automatic retention of page and control state, which means you don’t need to do anything about getting back the data of controls after posting page to the server.

Here, which is useful to us is the ViewState property, we can use it to save information between round trips to the server.
[c#]
//to save information
ViewState.Add(“shape”,”circle”);
//to retrieve information
string shapes=ViewState[“shape”];

Note: Unlike Hidden Field, the values in ViewState are invisible when ‘view source’, they are compressed and encoded.

State Management in ASP.NET

Web form pages are HTTP-Based, they are stateless, which means they don’t know whether the requests are all from the same client, and pages are destroyed and recreated with each round trip to the server, therefore information will be lost, therefore state management is really an issue in developing web applications

We could easily solve these problems in ASP with cookie, query string, application, session and so on. Now in ASP.NET, we still can use these functions, but they are richer and more powerful, so let’s dive into it.

Mainly there are two different ways to manage web page’s state: Client-side and Server-side.
1.Client-side state management :  

•  cookie  
• hidden field  
• View State
• Query strings 

2. Server-side state management: 

• Application object 
• Session object 
• Database