Page.RegisterRequiresControlState Method (Control)
.NET Framework (current version)
Registers a control as one whose control state must be persisted.
Assembly: System.Web (in System.Web.dll)
Parameters
- control
-
Type:
System.Web.UI.Control
The control to register.
| 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.
Class Sample Inherits Control Dim currentIndex As Integer Protected Overrides Sub OnInit(ByVal e As EventArgs) Page.RegisterRequiresControlState(Me) currentIndex = 0 MyBase.OnInit(e) End Sub Protected Overrides Function SaveControlState() As Object If currentIndex <> 0 Then Return CType(currentIndex, Object) Else Return Nothing End If End Function Protected Overrides Sub LoadControlState(ByVal state As Object) If (state <> Nothing) Then currentIndex = CType(state, Integer) End If End Sub End Class
.NET Framework
Available since 2.0
Available since 2.0
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