ViewState is the Mechanism that allows State values to be preserved across page PostBacks. Page level state information maintained, when an element on the Web form page causes a subsequent request to the server for the same page-referred to as postback. This is appropriately called View State as the data involved is usually, Though not necessarily. Shown to the user directly within page output. When the page is processed the current state of the page and controls is hashed into a string and saved in the page as a Hidden Field, when the page is posted back to the server. The page parses the viewstate string at page initialization and restores property information in the page. ViewState is enabled by default. ViewState is an another approach for saving data for the user. While Cookies and Session can be accessed from all your pages from your website. ViewState values are not carried between pages. Here is a simple example of using the Viewstate to carry values between PostBacks.