HttpContext 類別 (System.Web)

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語言篩選

本頁僅適用於

Microsoft Visual Studio 2008/.NET Framework 3.5

其他版本也適用於下列軟體：

Microsoft Visual Studio 2005/.NET Framework 2.0

.NET Framework 類別庫

HttpContext 類別

更新：2007 年 11 月

封裝所有關於個別 HTTP 要求的 HTTP 特定資訊。

命名空間： System.Web
組件： System.Web (在 System.Web.dll 中)

語法

Visual Basic (宣告)

<AspNetHostingPermissionAttribute(SecurityAction.LinkDemand, Level := AspNetHostingPermissionLevel.Minimal)> _
Public NotInheritable Class HttpContext _
    Implements IServiceProvider

Visual Basic (使用方式)

Dim instance As HttpContext

[AspNetHostingPermissionAttribute(SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
public sealed class HttpContext : IServiceProvider

Visual C++

[AspNetHostingPermissionAttribute(SecurityAction::LinkDemand, Level = AspNetHostingPermissionLevel::Minimal)]
public ref class HttpContext sealed : IServiceProvider

/** @attribute AspNetHostingPermissionAttribute(SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal) */
public final class HttpContext implements IServiceProvider

JScript

public final class HttpContext implements IServiceProvider

備註

繼承 IHttpModule 和 IHttpHandler 介面的類別具備對目前 HTTP 要求的 HttpContext 物件的參考。物件針對要求提供內建的 Request、Response 和 Server 屬性的存取。

HttpContext 是在 .NET Framework 3.5 版中引入。如需詳細資訊，請參閱 .NET Framework 3.5 架構。

Topic	Location
HOW TO：建立非同步的 HTTP 處理常式	建置 ASP .NET Web 應用程式
HOW TO：建立非同步的 HTTP 處理常式	在 Visual Studio 中建立 ASP .NET Web 應用程式
逐步解說：建立 ASP.NET 1.1 的自訂資料繫結 ASP.NET Web 控制項	撰寫 ASP.NET 控制項
逐步解說：建立 ASP.NET 1.1 的自訂資料繫結 ASP.NET Web 控制項	在 Visual Studio 中建立 ASP .NET Web 應用程式
逐步解說：建立 ASP.NET 2.0 的自訂資料繫結 ASP.NET Web 控制項	撰寫 ASP.NET 控制項
逐步解說：建立 ASP.NET 2.0 的自訂資料繫結 ASP.NET Web 控制項	在 Visual Studio 中建立 ASP .NET Web 應用程式
逐步解說：開發和使用自訂的伺服器控制項	撰寫 ASP.NET 控制項
逐步解說：開發和使用自訂的伺服器控制項	使用 Visual Web Developer 建置應用程式
開發 ASP.NET 1.1 的自訂資料繫結控制項	撰寫 ASP.NET 控制項
開發 ASP.NET 1.1 的自訂資料繫結控制項	在 Visual Studio 中建立 ASP .NET Web 應用程式
開發 ASP.NET 2.0 (含) 以上的自訂資料繫結控制項	在 Visual Studio 中建立 ASP .NET Web 應用程式
開發 ASP.NET 2.0 的自訂資料繫結控制項	撰寫 ASP.NET 控制項

範例

下列範例示範如何存取和顯示 HttpContext 物件的屬性。使用 Page 物件的 Context 屬性，可以存取目前 HTTP 要求的內容。

Visual Basic

<%@ 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  >
<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  >
<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>

使用權限

AspNetHostingPermission
在裝載環境中運作所需。要求值：LinkDemand；使用權限值：Minimal

繼承階層架構

System..::.Object
System.Web..::.HttpContext

執行緒安全

這個型別的任何 Public static (在 Visual Basic 中為 Shared) 成員都具備執行緒安全。並非所有的執行個體成員都是安全執行緒。

平台

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

.NET Framework 和 .NET Compact Framework 並不支援各種平台的所有版本。如需支援平台版本的相關資訊，請參閱 .NET Framework 系統需求。

版本資訊

.NET Framework

支援版本：3.5、3.0、2.0、1.1、1.0

請參閱

參考

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