ControlCachePolicy.Duration Property
Definition
Important
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Gets or sets the amount of time that cached items are to remain in the output cache.
public:
property TimeSpan Duration { TimeSpan get(); void set(TimeSpan value); };public TimeSpan Duration { get; set; }member this.Duration : TimeSpan with get, setPublic Property Duration As TimeSpanProperty Value
A TimeSpan that represents the amount of time a user control is to remain in the output cache. The default is Zero.
Exceptions
The user control is not associated with a BasePartialCachingControl and is not cacheable.
-or-
The Duration property is set outside of the initialization and rendering stages of the control.
Examples
The following code example demonstrates how a user control can be loaded dynamically and manipulated programmatically at run time. The PartialCachingAttribute attribute is applied to a user control named SimpleControl, which means it is wrapped by a PartialCachingControl control at run time. The SimpleControl object's caching settings can be programmatically manipulated through its associated ControlCachePolicy object, which is available through a reference to the PartialCachingControl control that wraps it. In this example, the Duration property is examined during page initialization and cache expiration is changed if some conditions are met. This example is part of a larger example provided for the ControlCachePolicy class.
<%@ Page Language="C#" %>
<%@ Reference Control="SimpleControl.ascx" %>
<script language="C#" runat="server">
// The following example demonstrates how to load a user control dynamically at run time, and
// work with the ControlCachePolicy object associated with it.
// Loads and displays a UserControl defined in a seperate Logonform.ascx file.
// You need to have "SimpleControl.ascx" file in
// the same directory as the aspx file.
void Page_Init(object sender, System.EventArgs e) {
// Obtain a PartialCachingControl object which wraps the 'LogOnControl' user control.
PartialCachingControl pcc = LoadControl("SimpleControl.ascx") as PartialCachingControl;
// If the control is slated to expire in greater than 60 Seconds
if (pcc.CachePolicy.Duration > TimeSpan.FromSeconds(60) )
{
// Make it expire faster. Set a new expiration time to 30 seconds, and make it
// an absolute expiration if it isnt already.
pcc.CachePolicy.SetExpires(DateTime.Now.Add(TimeSpan.FromSeconds(30)));
pcc.CachePolicy.SetSlidingExpiration(false);
}
Controls.Add(pcc);
}
</script>
<%@ Page Language="VB" %>
<%@ Reference Control="SimpleControl.ascx" %>
<script language="VB" runat="server">
' The following example demonstrates how to load a user control dynamically at run time, and
' work with the ControlCachePolicy object associated with it.
' Loads and displays a UserControl defined in a seperate Logonform.ascx file.
' You need to have "SimpleControl.ascx" file in
' the same directory as the aspx file.
Sub Page_Init(ByVal sender As Object, ByVal e As System.EventArgs)
' Obtain a PartialCachingControl object which wraps the 'LogOnControl' user control.
Dim pcc As PartialCachingControl
pcc = LoadControl("SimpleControl.ascx")
' If the control is slated to expire in greater than 60 Seconds
If (pcc.CachePolicy.Duration > TimeSpan.FromSeconds(60)) Then
' Make it expire faster. Set a new expiration time to 30 seconds, and make it
' an absolute expiration if it isnt already.
pcc.CachePolicy.SetExpires(DateTime.Now.Add(TimeSpan.FromSeconds(30)))
pcc.CachePolicy.SetSlidingExpiration(False)
End If
Controls.Add(pcc)
End Sub
</script>
Remarks
If an absolute expiration policy is set using the SetSlidingExpiration method, the Duration property returns the amount of time remaining until cache entry expiration.
