DataSourceCacheExpiry Enumeration (System.Web.UI)

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.NET Framework Class Library
DataSourceCacheExpiry Enumeration

Note: This enumeration is new in the .NET Framework version 2.0.

Describes the way data cached using ASP.NET caching mechanisms expires when a time-out is set.

Namespace: System.Web.UI
Assembly: System.Web (in system.web.dll)

Syntax
Visual Basic (Declaration)
Public Enumeration DataSourceCacheExpiry
Visual Basic (Usage)
Dim instance As DataSourceCacheExpiry
C#
public enum DataSourceCacheExpiry
C++
public enum class DataSourceCacheExpiry
J#
public enum DataSourceCacheExpiry
JScript
public enum DataSourceCacheExpiry
Members
  Member name Description
Absolute Cached data expires when the amount of time specified by the CacheDuration property has passed since the data was first cached. 
Sliding Cached data expires only when the cache entry has not been used for the amount of time specified by the CacheDuration property. 
Remarks

The DataSourceCacheExpiry enumeration describes how data cached by a data source control expires in the ASP.NET cache. An ASP.NET data source control caches data in the ASP.NET cache based on a specified time-out period, which is set using the CacheDuration property. The DataSourceCacheExpiry describes how this time-out setting is used. If the expiration policy is set to Absolute, the cached data is discarded when the amount of time specified passes since the data was first cached. If the expiration policy is set to Sliding, the cached data is discarded only when the cache entry has not been used for the amount of time specified.

Example

The following code example demonstrates how to use the DataSourceCacheExpiry enumeration declaratively. In this example, a SqlDataSource control is used to display data in a GridView control. The SqlDataSource control has caching enabled and its CacheExpirationPolicy set to Sliding, to cache data as long as there is activity.

Visual Basic
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<HTML>
    <BODY>
        <FORM runat="server">

            <asp:SqlDataSource
                id="SqlDataSource1"
                runat="server"
                DataSourceMode="DataSet"
                ConnectionString="<%$ ConnectionStrings:MyNorthwind%>"
                EnableCaching="True"
                CacheDuration="20"
                CacheExpirationPolicy="Sliding"
                SelectCommand="SELECT EmployeeID,FirstName,LastName,Title FROM Employees">
            </asp:SqlDataSource>

            <asp:GridView
                id="GridView1"
                runat="server"
                AutoGenerateColumns="False"
                DataSourceID="SqlDataSource1">
                <columns>
                    <asp:BoundField HeaderText="First Name" DataField="FirstName" />
                    <asp:BoundField HeaderText="Last Name" DataField="LastName" />
                    <asp:BoundField HeaderText="Title" DataField="Title" />
                </columns>
            </asp:GridView>

        </FORM>
    </BODY>
</HTML>
C#
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<HTML>
    <BODY>
        <FORM runat="server">

            <asp:SqlDataSource
                id="SqlDataSource1"
                runat="server"
                DataSourceMode="DataSet"
                ConnectionString="<%$ ConnectionStrings:MyNorthwind%>"
                EnableCaching="True"
                CacheDuration="20"
                CacheExpirationPolicy="Sliding"
                SelectCommand="SELECT EmployeeID,FirstName,LastName,Title FROM Employees">
            </asp:SqlDataSource>

            <asp:GridView
                id="GridView1"
                runat="server"
                AutoGenerateColumns="False"
                DataSourceID="SqlDataSource1">
                <columns>
                    <asp:BoundField HeaderText="First Name" DataField="FirstName" />
                    <asp:BoundField HeaderText="Last Name" DataField="LastName" />
                    <asp:BoundField HeaderText="Title" DataField="Title" />
                </columns>
            </asp:GridView>

        </FORM>
    </BODY>
</HTML>
J#
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<HTML>
    <BODY>
        <FORM runat="server">

            <asp:SqlDataSource
                id="SqlDataSource1"
                runat="server"
                DataSourceMode="DataSet"
                ConnectionString="Data Source=localhost;Integrated Security=SSPI;Initial Catalog=Northwind;"
                EnableCaching="True"
                CacheDuration="20"
                CacheExpirationPolicy="Sliding"
                SelectCommand="SELECT EmployeeID,FirstName,LastName,Title FROM Employees">
            </asp:SqlDataSource>

            <asp:GridView
                id="GridView1"
                runat="server"
                AutoGenerateColumns="False"
                DataSourceID="SqlDataSource1">
                <Columns>
                    <asp:BoundField HeaderText="First Name" DataField="FirstName" />
                    <asp:BoundField HeaderText="Last Name" DataField="LastName" />
                    <asp:BoundField HeaderText="Title" DataField="Title" />
                </Columns>
            </asp:GridView>

        </FORM>
    </BODY>
</HTML>
Platforms

Windows 98, Windows 2000 SP4, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

Version Information

.NET Framework

Supported in: 2.0
See Also

Reference

System.Web.UI Namespace

Other Resources

ASP.NET Caching