HttpContext クラスとは何？わかりやすく解説 Weblio辞書

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.NET Framework クラスライブラリリファレンス

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HttpContext クラス

それぞれの HTTP 要求に関する HTTP 固有のすべての情報をカプセル化します。

名前空間: System.Web
アセンブリ: System.Web (system.web.dll 内)
構文

Visual Basic (宣言)

Public NotInheritable Class
 HttpContext
    Implements IServiceProvider

Visual Basic (使用法)

Dim instance As HttpContext

public sealed class HttpContext : IServiceProvider

C++

public ref class HttpContext sealed : IServiceProvider

public final class HttpContext implements IServiceProvider

JScript

public final class HttpContext implements IServiceProvider

解説

IHttpModule インターフェイスおよび IHttpHandler インターフェイスを継承するクラスには、現在の HTTP 要求の HttpContext オブジェクトへの参照が用意されています。このオブジェクトは、要求に組み込まれる Request、Response、および Server 各プロパティへのアクセスを実現します。

Topic	Location
チュートリアル : カスタムサーバーコントロールの開発と使用	ASP.NET コントロールの作成
方法 : 非同期 HTTP ハンドラを作成する	ASP .NET Web アプリケーションの作成

使用例

HttpContext オブジェクトのプロパティにアクセスして表示する方法を次のコード例に示します。現在の HTTP 要求のコンテキストにアクセスするには、Page オブジェクトの Context プロパティを使用します。

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>