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WebRequest.DefaultCachePolicy Property

Gets or sets the default cache policy for this request.

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

'Declaration
Public Shared Property DefaultCachePolicy As RequestCachePolicy

Property Value

Type: System.Net.Cache.RequestCachePolicy
A HttpRequestCachePolicy that specifies the cache policy in effect for this request when no other policy is applicable.

This policy is used for this request if the following conditions exist:

  • There is no DefaultCachePolicy property specified for this request.

  • The machine and application configuration files do not specify a cache policy that is applicable to the Uniform Resource Identifier (URI) used to create this request.

The cache policy determines whether the requested resource can be taken from a cache instead of sending the request to the resource host computer.

A copy of a resource is only added to the cache if the response stream for the resource is retrieved and read to the end of the stream. So another request for the same resource could use a cached copy, depending on the cache policy level for this request.

The following code example demonstrates setting the default cache policy for Web requests.


Public Shared Function GetResponseFromServer2(ByVal uri As Uri) As WebResponse
    Dim policy As New RequestCachePolicy(RequestCacheLevel.NoCacheNoStore)
    Dim request As WebRequest = WebRequest.Create(uri)
    WebRequest.DefaultCachePolicy = policy
    Dim response As WebResponse = request.GetResponse()
    Console.WriteLine("Policy is {0}.", policy.ToString())
    Console.WriteLine("Is the response from the cache? {0}", response.IsFromCache)
    Return response
End Function


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

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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