Page.RegisterRequiresControlState Method
Registers a control as one whose control state must be persisted.
Assembly: System.Web (in System.Web.dll)
| Exception | Condition |
|---|---|
| ArgumentException |
The control to register is null. |
| InvalidOperationException |
The RegisterRequiresControlState method can be called only before or during the PreRender event. |
Custom server controls that use control state must call the RegisterRequiresControlState method on each request because registration for control state is not carried over from request to request during a postback event. It is recommended that registration occur in the Init event.
The following code example shows a custom server control calling the RegisterRequiresControlState method.
public class Sample : Control { private int currentIndex = 0; protected override void OnInit(EventArgs e) { Page.RegisterRequiresControlState(this); base.OnInit(e); } protected override object SaveControlState() { return currentIndex != 0 ? (object)currentIndex : null; } protected override void LoadControlState(object state) { if (state != null) { currentIndex = (int)state; } } }
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
