HttpContext-Klasse
Kapselt alle HTTP-spezifischen Informationen über eine einzelne HTTP-Anforderung.
Namespace: System.Web
Assembly: System.Web (in system.web.dll)
Syntax
'Declaration
Public NotInheritable Class HttpContext
Implements IServiceProvider
'Usage
Dim instance As HttpContext
public sealed class HttpContext : IServiceProvider
public ref class HttpContext sealed : IServiceProvider
public final class HttpContext implements IServiceProvider
public final class HttpContext implements IServiceProvider
Hinweise
Klassen, die die IHttpModule-Schnittstelle und die IHttpHandler-Schnittstelle erben, wird ein Verweis auf ein HttpContext-Objekt für die aktuelle HTTP-Anforderung bereitgestellt. Über das Objekt kann auf die systeminternen Eigenschaften Request, Response und Server für die Anforderung zugegriffen werden.
Beispiel
Im folgenden Codebeispiel wird veranschaulicht, wie auf Eigenschaften des HttpContext-Objekts zugegriffen wird und wie diese angezeigt werden. Auf den Kontext der aktuellen HTTP-Anforderung wird mit der Context-Eigenschaft des Page-Objekts zugegriffen.
<%@ Page Language="VB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)
' The HttpContext associated with the page can be accessed by the Context property.
Dim sb As New System.Text.StringBuilder()
' Use the current HttpContext object to determine if custom errors are enabled.
sb.Append("Is custom errors enabled: " & _
Context.IsCustomErrorEnabled.ToString() & "<br/>")
' Use the current HttpContext object to determine if debugging is enabled.
sb.Append("Is debugging enabled: " & _
Context.IsDebuggingEnabled.ToString() & "<br/>")
' Use the current HttpContext object to access the current TraceContext object.
sb.Append("Trace Enabled: " & _
Context.Trace.IsEnabled.ToString() & "<br/>")
' Use the current HttpContext object to access the current HttpApplicationState object.
sb.Append("Number of items in Application state: " & _
Context.Application.Count.ToString() & "<br/>")
' Use the current HttpContext object to access the current HttpSessionState object.
' Session state may not be configured.
Try
sb.Append("Number of items in Session state: " & _
Context.Session.Count.ToString() & "<br/>")
Catch ex As Exception
sb.Append("Session state not enabled. <br/>")
End Try
' Use the current HttpContext object to access the current Cache object.
sb.Append("Number of items in the cache: " & _
Context.Cache.Count.ToString() & "<br/>")
' Use the current HttpContext object to determine the timestamp for the current HTTP Request.
sb.Append("Timestamp for the HTTP request: " & _
Context.Timestamp.ToString() & "<br/>")
' Assign StringBuilder object to output label.
OutputLabel.Text = sb.ToString()
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>HttpContext Example</title>
</head>
<body>
<form id="form1" runat="server">
<div>
Using the current HttpContext to get information about the current page.
<br />
<asp:Label id="OutputLabel" runat="server"></asp:Label>
</div>
</form>
</body>
</html>
<%@ Page Language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
protected void Page_Load(object sender, EventArgs e)
{
// The HttpContext associated with the page can be accessed by the Context property.
System.Text.StringBuilder sb = new System.Text.StringBuilder();
// Use the current HttpContext object to determine if custom errors are enabled.
sb.Append("Is custom errors enabled: " +
Context.IsCustomErrorEnabled.ToString() + "<br/>");
// Use the current HttpContext object to determine if debugging is enabled.
sb.Append("Is debugging enabled: " +
Context.IsDebuggingEnabled.ToString() + "<br/>");
// Use the current HttpContext object to access the current TraceContext object.
sb.Append("Trace Enabled: " +
Context.Trace.IsEnabled.ToString() + "<br/>");
// Use the current HttpContext object to access the current HttpApplicationState object.
sb.Append("Number of items in Application state: " +
Context.Application.Count.ToString() + "<br/>");
// Use the current HttpContext object to access the current HttpSessionState object.
// Session state may not be configured.
try
{
sb.Append("Number of items in Session state: " +
Context.Session.Count.ToString() + "<br/>");
}
catch
{
sb.Append("Session state not enabled. <br/>");
}
// Use the current HttpContext object to access the current Cache object.
sb.Append("Number of items in the cache: " +
Context.Cache.Count.ToString() + "<br/>");
// Use the current HttpContext object to determine the timestamp for the current HTTP Request.
sb.Append("Timestamp for the HTTP request: " +
Context.Timestamp.ToString() + "<br/>");
// Assign StringBuilder object to output label.
OutputLabel.Text = sb.ToString();
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>HttpContext Example</title>
</head>
<body>
<form id="form1" runat="server">
<div>
Using the current HttpContext to get information about the current page.
<br />
<asp:Label id="OutputLabel" runat="server"></asp:Label>
</div>
</form>
</body>
</html>
Vererbungshierarchie
System.Object
System.Web.HttpContext
Threadsicherheit
Alle öffentlichen statischen (Shared in Visual Basic) Member dieses Typs sind threadsicher. Bei Instanzmembern ist die Threadsicherheit nicht gewährleistet.
Plattformen
Windows 98, Windows 2000 SP4, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
.NET Framework unterstützt nicht alle Versionen sämtlicher Plattformen. Eine Liste der unterstützten Versionen finden Sie unter Systemanforderungen.
Versionsinformationen
.NET Framework
Unterstützt in: 2.0, 1.1, 1.0
Siehe auch
Referenz
HttpContext-Member
System.Web-Namespace
IHttpModule
IHttpHandler