Saves any server control state changes that have occurred since the time the page was posted back to the server.
Assembly: System.Web (in System.Web.dll)
Use the method to save state information required for the operation of a specific control. This control-state data is stored separately from the control's view-state data.Notes to Inheritors
When control state is saved, a string object is returned to the client as a variable that is stored in an HTML HIDDEN element. Override this method to extract the state information to use in your control.
Control state is intended for small amounts of critical data, such as a page index or a keyword. Using control state for large amounts of data can adversely affect page performance. For more information, see ASP.NET State Management Overview.
The following code example overrides the method in a custom ASP.NET control. When this method is invoked, it determines whether the internal property currentIndex is set to a non-default value and, if so, saves the value to control state.
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