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WebMethodAttribute.CacheDuration Property

Gets or sets the number of seconds the response should be held in the cache.

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

public int CacheDuration { get; set; }

Property Value

Type: System.Int32
The number of seconds the response should be held in the cache. The default is 0, which means the response is not cached.

When caching is enabled requests and responses are held in memory on the server for at least the cache duration so caution must be used if you expect requests or responses to be very large or you expect requests to vary widely.

There are two issues that can affect output caching in an ASP.NET 2.0 Web service application.

In ASP.NET 2.0 the HTTP method of the test page has changed from GET to POST. However, POSTs are not normally cached. If you change the test page in an ASP.NET 2.0 Web service application to use GET, caching works properly.

In addition, HTTP indicates that a user agent (the browser or calling application) should be able to override server caching by setting the "Cache-Control" to "no-cache". ASP.NET applications, therefore, ignore cached results when they find a "no-cache" header.

The following example places the result of the call to the ServiceUsage XML Web service method in the cache for 60 seconds. Any time an XML Web service client executes the ServiceUsage XML Web service method during that time, the same result is returned.

<%@ WebService Language="C#" Class="Counter" %>

using System.Web.Services;
using System;
using System.Web;

public class Counter : WebService {

     [ WebMethod(Description="Number of times this service has been accessed",
     CacheDuration=60,MessageName="ServiceUsage") ]
     public int ServiceUsage() {
          // If the XML Web service has not been accessed, initialize it to 1. 
          if (Application["MyServiceUsage"] == null) {
              Application["MyServiceUsage"] = 1;
          else {
              // Increment the usage count.
              Application["MyServiceUsage"] = ((int) Application["MyServiceUsage"]) + 1;

          // Return the usage count.      
          return  (int) Application["MyServiceUsage"];

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

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

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0