HttpCachePolicy.SetAllowResponseInBrowserHistory Method (System.Web)

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.NET Framework Class Library

HttpCachePolicy.SetAllowResponseInBrowserHistory Method

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Makes the response is available in the client browser History cache, regardless of the HttpCacheability setting made on the server, when the allow parameter is true.

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

Syntax

Visual Basic


Public Sub SetAllowResponseInBrowserHistory ( _
	allow As Boolean _
)


public void SetAllowResponseInBrowserHistory(
	bool allow
)

Visual C++


public:
void SetAllowResponseInBrowserHistory(
	bool allow
)


member SetAllowResponseInBrowserHistory : 
        allow:bool -> unit

Parameters

allow: Type: System.Boolean
true to direct the client browser to store responses in the History folder; otherwise false. The default is false.

Remarks

When HttpCacheability is set to NoCache or ServerAndNoCache the Expires HTTP header is by default set to -1; this tells the client not to cache responses in the History folder, so that when you use the back/forward buttons the client requests a new version of the response each time. You can override this behavior by calling the SetAllowResponseInBrowserHistory method with the allow parameter set to true.

If HttpCacheability is set to values other than NoCache or ServerAndNoCache, calling the SetAllowResponseInBrowserHistory method with either value for allow has no effect.

SetAllowResponseInBrowserHistory is introduced in the .NET Framework version 3.5. For more information, see .NET Framework Versions and Dependencies.

Examples

The following code example demonstrates how to override the SetAllowResponseInBrowserHistory method to direct the client to store the responses in its history in a custom HttpCachePolicy.

Visual Basic


<%@ Page language="VB" AutoEventWireup="true" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head>
    <title>HttpCachePolicy - SetAllowResponseInBrowserHistory - Visual Basic .NET Example</title>
    <script runat="server">
      Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) 

          ' When HttpCacheability is set to NoCache or ServerAndNoCache 
          ' the Expires HTTP header is set to -1 by default. This instructs 
          ' the client to not cache responses in the History folder. Thus, 
          ' each time you use the back/forward buttons, the client requests 
          ' a new version of the response. 
          HttpContext.Current.Response.Cache.SetCacheability(HttpCacheability.ServerAndNoCache)

          ' Override the ServerAndNoCache behavior by setting the SetAllowInBrowserHistory 
          ' method to true. This directs the client browser to store responses in  
          ' its History folder.
          HttpContext.Current.Response.Cache.SetAllowResponseInBrowserHistory(True)

          ' Display the DateTime value.
          Label1.Text = DateTime.Now.ToLongTimeString()
      End Sub
    </script>
  </head>
  <body>
    <form id="Form1" method="post" runat="server">
      <h3>HttpCachePolicy - SetAllowResponseInBrowserHistory - Visual Basic .NET</h3>

      <p>Click the Submit button a few times, and then click the Browser's Back button.<br />
        The page should be stored in the Browser's History folder</p>

      <p>Time: <asp:Label id="Label1" runat="server" Font-Bold="True" ForeColor="Red" /></p>

      <asp:Button id="Button1" runat="server" Text="Submit" />
    </form>
  </body>
</html>


<%@ Page language="c#" AutoEventWireup="true" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head>
    <title>HttpCachePolicy - SetAllowResponseInBrowserHistory - C# Example</title>
    <script runat="server">
      void Page_Load(Object sender, EventArgs e) 
      {
        // When HttpCacheability is set to NoCache or ServerAndNoCache 
        // the Expires HTTP header is set to -1 by default. This instructs 
        // the client to not cache responses in the History folder. Thus, 
        // each time you use the back/forward buttons, the client requests 
        // a new version of the response. 
        HttpContext.Current.Response.Cache.SetCacheability(HttpCacheability.ServerAndNoCache);

        // Override the ServerAndNoCache behavior by setting the SetAllowInBrowserHistory 
        // method to true. This directs the client browser to store responses in  
        // its History folder.
        HttpContext.Current.Response.Cache.SetAllowResponseInBrowserHistory(true);

        // Display the DateTime value.
        Label1.Text = DateTime.Now.ToLongTimeString();
      }
    </script>
  </head>
  <body>
    <form id="Form1" method="post" runat="server">
      <h3>HttpCachePolicy - SetAllowResponseInBrowserHistory - C# Example</h3>

      <p>Click the Submit button a few times, and then click the Browser's Back button.<br />
        The page should be stored in the Browser's History folder</p>

      <p>Time: <asp:Label id="Label1" runat="server" Font-Bold="True" ForeColor="Red" /></p>

      <asp:Button id="Button1" runat="server" Text="Submit" />
    </form>
  </body>
</html>

Version Information

.NET Framework

Supported in: 4.5, 4, 3.5, 3.0, 2.0, 1.1

Platforms

Windows 8 Release Preview, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 SP2, Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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

Reference

HttpCachePolicy Class

System.Web Namespace