asp.net - ログイン後、Asp.Net Application_Start が再度呼び出されます

Question

VS でコードをデバッグすると、Global.asax の Application_Start メソッドが 2 回呼び出されていることがわかりました。

• まずサーバー起動時
• ログイン後2回目

login メソッドは次のことを行います。

  AuthenticationCookie.SetSessionCookie(userName);
  FormsAuthentication.RedirectFromLoginPage(userName, false);
  System.Threading.Thread.CurrentPrincipal = user;

Web.config ファイルは次のとおりです (一部の 100% 無関係な部分を除く)。

. . .

<appSettings>
    <add key="webpages:Version" value="2.0.0.0" />
    <add key="webpages:Enabled" value="false" />
    <add key="ClientValidationEnabled" value="true" />
    <add key="UnobtrusiveJavaScriptEnabled" value="true" />
</appSettings>
<!--
For a description of web.config changes for .NET 4.5 see http://go.microsoft.com/fwlink/?LinkId=235367.

The following attributes can be set on the <httpRuntime> tag.


  <system.net>
    <settings>
      <httpWebRequest useUnsafeHeaderParsing="true" />
    </settings>
  </system.net>

  <system.web>
    <compilation debug="true" targetFramework="4.5" />
        <authentication mode="Forms">
            <forms loginUrl="SignIn" protection="All" timeout="120" />
        </authentication>
        <pages controlRenderingCompatibilityVersion="4.0">
            <namespaces>
                <add namespace="System.Web.Helpers" />
                <add namespace="System.Web.Mvc" />
                <add namespace="System.Web.Mvc.Ajax" />
                <add namespace="System.Web.Mvc.Html" />
                <add namespace="System.Web.Optimization" />
                <add namespace="System.Web.Routing" />
                <add namespace="System.Web.WebPages" />
            </namespaces>
        </pages>
        <!--
            If you are deploying to a cloud environment that has multiple web server instances,
            you should change session state mode from "InProc" to "Custom". In addition,
            change the connection string named "DefaultConnection" to connect to an instance
            of SQL Server (including SQL Azure and SQL  Compact) instead of to SQL Server Express.
      -->
        <sessionState mode="InProc" customProvider="DefaultSessionProvider" timeout="120">
            <providers>
                <add name="DefaultSessionProvider" type="System.Web.Providers.DefaultSessionStateProvider, System.Web.Providers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" connectionStringName="DefaultConnection" />
            </providers>
        </sessionState>
    </system.web>
    <system.webServer>
        <validation validateIntegratedModeConfiguration="false" />
        <modules runAllManagedModulesForAllRequests="true" />
        <handlers>
            <remove name="ExtensionlessUrlHandler-ISAPI-4.0_32bit" />
            <remove name="ExtensionlessUrlHandler-ISAPI-4.0_64bit" />
            <remove name="ExtensionlessUrlHandler-Integrated-4.0" />
            <add name="ExtensionlessUrlHandler-ISAPI-4.0_32bit" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll" preCondition="classicMode,runtimeVersionv4.0,bitness32" responseBufferLimit="0" />
            <add name="ExtensionlessUrlHandler-ISAPI-4.0_64bit" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll" preCondition="classicMode,runtimeVersionv4.0,bitness64" responseBufferLimit="0" />
            <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />
        </handlers>
    </system.webServer>