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.NET Framework 2.0
XmlDataSource Class
 CacheDuration Property
This page is specific to
Microsoft Visual Studio 2005/.NET Framework 2.0

Other versions are also available for the following:
.NET Framework Class Library
XmlDataSource.CacheDuration Property

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

Gets or sets the length of time, in seconds, that the data source control caches data it has retrieved.

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

Visual Basic (Declaration)
Public Overridable Property CacheDuration As Integer
Visual Basic (Usage)
Dim instance As XmlDataSource
Dim value As Integer

value = instance.CacheDuration

instance.CacheDuration = value
C#
public virtual int CacheDuration { get; set; }
C++
public:
virtual property int CacheDuration {
    int get ();
    void set (int value);
}
J#
/** @property */
public int get_CacheDuration ()

/** @property */
public void set_CacheDuration (int value)
JScript
public function get CacheDuration () : int

public function set CacheDuration (value : int)

Property Value

The number of seconds that the XmlDataSource control caches the results of a data retrieval operation. The default value is 0.

The XmlDataSource control automatically caches data when the following applies:

  • The EnableCaching property is set to true.

  • The CacheDuration property is set to a value greater than 0, which indicates the number of seconds that the cache stores data before the cache is invalidated.

Any change to the Data property or the contents of the file that contains the XML data causes the cache to be invalidated.

By default, the CacheDuration property is set to 0, which indicates an indefinite cache, and the data source will cache data until the XML file that it depends on is changed.

The behavior of the cache is governed by a combination of the duration and the CacheExpirationPolicy setting. If CacheExpirationPolicy is set to Absolute, the XmlDataSource control caches data on the first data retrieval operation, holds it in memory for the amount of time specified by CacheDuration, and invalidates it after the time has lapsed. The cache is then refreshed upon the next operation. If CacheExpirationPolicy is set to Sliding, the data source control caches data on the first data retrieval operation, but resets the time window that it holds the cache for upon each subsequent operation. The cache will only expire if there is no activity for a time equal to the CacheDuration since the last data retrieval.

The following code example demonstrates how to enable caching when using the XmlDataSource control to display data contained in an XML file. Caching is enabled when the EnableCaching property is set to true and the CacheDuration is set to the number of seconds that the data is cached by the data source control.

Visual Basic
<%@ Page Language="VB" %>
<!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:xmldatasource
        id="XmlDataSource1"
        runat="server"
        datafile="books.xml"
        enablecaching="True"
        cacheduration="60"
        cacheexpirationPolicy="Sliding" />

      <!- TreeView uses hierachical data, so the
          XmlDataSource uses an XmlHierarchicalDataSourceView
          when a TreeView is bound to it. -->

      <asp:treeview
        id="TreeView1"
        runat="server"
        datasourceid="XmlDataSource1">
        <databindings>
          <asp:treenodebinding datamember="book" textfield="title"/>
        </databindings>
      </asp:treeview>

    </form>
  </BODY>
</HTML>
C#
<%@ Page Language="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:xmldatasource
        id="XmlDataSource1"
        runat="server"
        datafile="books.xml"
        enablecaching="True"
        cacheduration="60"
        cacheexpirationpolicy="Sliding" />

      <!- TreeView uses hierachical data, so the
          XmlDataSource uses an XmlHierarchicalDataSourceView
          when a TreeView is bound to it. -->

      <asp:treeview
        id="TreeView1"
        runat="server"
        datasourceid="XmlDataSource1">
        <databindings>
          <asp:treenodebinding datamember="book" textfield="title"/>
        </databindings>
      </asp:treeview>

    </form>
  </BODY>
</HTML>
J#
<%@ Page Language="VJ#" %>
<!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:xmldatasource
        id="XmlDataSource1"
        runat="server"
        datafile="books.xml"
        enablecaching="True"
        cacheduration="60"
        cacheexpirationpolicy="Sliding" />

      <!- TreeView uses hierachical data, so the
          XmlDataSource uses an XmlHierarchicalDataSourceView
          when a TreeView is bound to it. -->

      <asp:treeview
        id="TreeView1"
        runat="server"
        datasourceid="XmlDataSource1">
        <databindings>
          <asp:treenodebinding datamember="book" textfield="title"/>
        </databindings>
      </asp:treeview>

    </form>
  </BODY>
</HTML>

The XML file in the code example has the following data:

<books>
   <computerbooks>
     <book title="Secrets of Silicon Valley" author="Sheryl Hunter"/>
     <book title="Straight Talk About Computers" author="Dean Straight"/>
     <book title="You Can Combat Computer Stress!" author="Marjorie Green"/>
   </computerbooks>
   <cookbooks>
     <book title="Silicon Valley Gastronomic Treats" author="Innes del Castill"/>
   </cookbooks>
</books>

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.

.NET Framework

Supported in: 2.0
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