How to display data from database into textbox, and update it

I can display my data in my textbox, dropdownlist after retrieve data from sql database, but when i proceed with my update button, the information edited in the textbox or dropdownlist wouldn’t update into the database. I tried to remove the code in page load, and re-key in all the data manually, it can be update. All I want is retrieve data from database and display it in the textbox, and it can be update into the database after make some changes from the textbox. Can someone help me on this? Thanks.

How to restrict unlogged/unauthorized users from viewing web pages in ASP.NET

I have some created web forms and I need to check whether the user is authenticated or not, before displaying the other web forms. All the users can access Default.aspx and About.aspx pages.
And I have three types of users namely- Admin,User and Super User. Also, I keep the authentication details in my own SQL server db.