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HttpCacheVaryByParams Class

.NET Framework 4

Provides a type-safe way to set the VaryByParams property.

System.Object
  System.Web.HttpCacheVaryByParams

Namespace:  System.Web
Assembly:  System.Web (in System.Web.dll)
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public sealed class HttpCacheVaryByParams

The HttpCacheVaryByParams type exposes the following members.

  Name Description
Public method HttpCacheVaryByParams Initializes a new instance of the HttpCacheVaryByParams class.
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  Name Description
Public property IgnoreParams Gets or sets a value indicating whether an HTTP response varies by Get or Post parameters.
Public property Item Gets or sets a value indicating whether the cache varies according to the specified HTTP request parameter.
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  Name Description
Public method Equals(Object) Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
Protected method Finalize Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public method GetHashCode Serves as a hash function for a particular type. (Inherited from Object.)
Public method GetType Gets the Type of the current instance. (Inherited from Object.)
Protected method MemberwiseClone Creates a shallow copy of the current Object. (Inherited from Object.)
Public method ToString Returns a string that represents the current object. (Inherited from Object.)
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The VaryByParams property identifies which HTTP Get or Post parameters ASP.NET uses to uniquely identify a variation of the response when there are multiple cached responses for a resource. This is useful when a response depends on a set of client inputs, such as headers or parameters.

The HttpCacheVaryByParams is not directly related to HTTP cache-control headers, but helps ensure that a client or proxy varies by the specified parameters. For more information about VaryByParams, see RFC 2616: Hypertext Transfer Protocol -- HTTP/1.1, available on the World Wide Web Consortium (W3C) Web site. See section 14, "Header Field Definitions", for complete details.

The following code example demonstrates how the HttpCacheVaryByParams object is accessed from the HttpCachePolicy object associated with an HttpResponse.

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Response.Cache.SetExpires(DateTime.Now.AddSeconds(60));
Response.Cache.SetCacheability(HttpCacheability.Public);
Response.Cache.SetValidUntilExpires(false);
Response.Cache.VaryByParams["Category"] = true;

if (Response.Cache.VaryByParams["Category"])
{
   //...
}

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

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.
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
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