HttpResponse.AddCacheDependency Method

Associates a set of cache dependencies with the response to facilitate invalidation of the response if it is stored in the output cache and the specified dependencies change.

Namespace:  System.Web
Assembly:  System.Web (in System.Web.dll)

public void AddCacheDependency(
	params CacheDependency[] dependencies
)

Parameters

dependencies
Type: System.Web.Caching.CacheDependency[]
A file, cache key, or CacheDependency to add to the list of application dependencies.

ExceptionCondition
ArgumentNullException

The dependencies parameter is null.

InvalidOperationException

This method was called too late in the cache processing pipeline, after the cached response was already created.

The AddCacheDependency method allows dependencies to be created between cached responses and a CacheDependency object.

The following example demonstrates how to create a cache dependency by using the AddCacheDependency method and a CacheDependency object.


<%@ Page Language="C#" %>
<%@ outputcache duration="30" varybyparam="none" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="Server">
    private void Page_Load(object sender, System.EventArgs e)
    {
        // Create a Cache Dependency 
        // using a CacheDependency object.
        CacheDependency authorsDependency = new CacheDependency("authors.xml");


        // Make the page invalid if either of the
        // cached items change or expire.        
        Response.AddCacheDependency(authorsDependency);

        // Display the current time for cache reference
        lblOutputCacheMsg.Text = DateTime.Now.ToString();
    }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
    <title>Cache Dependencies</title> 
</head>
<body>
    <form id="Form1" method="post" runat="server">
        <table>
            <tbody>
                <tr>
                    <td style="WIDTH: 118px">
                        The page was generated at:</td>
                    <td>
                        <asp:Label id="lblOutputCacheMsg" runat="server"></asp:Label>
                    </td>
                </tr>
            </tbody>
        </table>
    </form>
</body>
</html>


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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