What for ? Sharepoint’s API provides some standard form controls to render each column. This is the controls used to render the standard add and edit forms. And they all inherit the BaseFieldControl class. In other word: In any SPList, you have some SPField fields and each of these SPField has the super power to create a BaseFieldControl. Each BaseFieldControl is a CompositeControl containing ASP.Net controls. For a single line field, you will just have a wrapped TextBox.