What is ViewState and how is it used in ASP.NET?

ViewState in ASP.NET is a client-side state management technique used to preserve the state of a web page across postbacks. It stores the state of server-side controls on the web form and sends it back and forth between the server and client.

ViewState is used to maintain the state of controls like textboxes, dropdowns, checkboxes, and other web controls between postbacks. It helps in retaining data and control values even after the page is refreshed or submitted.

To enable ViewState in ASP.NET, you can set the EnableViewState property to true at the page or control level. ViewState is serialized and sent to the client as a hidden field, and then deserialized on postback to restore the control state.

Overall, ViewState is a helpful mechanism in ASP.NET for maintaining the state of web controls and enhancing user experience. It is essential for efficient web development and ensuring data persistence across multiple requests.