The specified control, or null if the specified control does not exist.
Use Control.FindControl(string) to access a control from a function in a code-behind page, to access a control that is inside another container, or in other circumstances where the target control is not directly accessible to the caller. This method will find a control only if the control is directly contained by the specified container; that is, the method does not search throughout a hierarchy of controls within controls. For information about how to find a control when you do not know its immediate container, see How to: Access Server Controls by ID.