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HttpResponse.SubStatusCode Property

Gets or sets a value qualifying the status code of the response.

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

public int SubStatusCode { get; set; }

Property Value

Type: System.Int32
An integer value that represents the IIS 7.0 substatus code.


The operation requires the integrated pipeline mode in IIS 7.0 and at least the .NET Framework version 3.0.


The status code is set after all HTTP headers have been sent.

The SubStatusCode property is only supported with the integrated pipeline mode in IIS 7.0 and at least the .NET Framework version 3.0. When you set the SubStatusCode property, the status is logged on IIS 7.0 if failed-request tracing is configured. Independent of whether tracing is configured, the code is never sent as part of the final response to the request. For more information, see Troubleshooting Failed Requests Using Failed Request Tracing in IIS 7.0.

The following example sets the SubStatusCode property in an event handler for the HttpApplication instance of the PostAuthenticateRequest event. Put the code file in the App_Code folder of your Web application and configure the Web.config file to register the module. For more information, see Walkthrough: Creating and Registering a Custom HTTP Module.

using System;
using System.Data;
using System.Web;
using System.Web.Security;
using System.Web.UI;

// Module that sets Response.SubStatusCode in PostAuthenticateRequest event handler. 
namespace Samples
    public class ModuleExampleTestCS : IHttpModule
        public ModuleExampleTestCS()
            // Constructor
        public void Init(HttpApplication app)
            app.PostAuthenticateRequest += new EventHandler(PostAuthenticateRequest_Handler);
        public void Dispose()
        public void PostAuthenticateRequest_Handler(object source, EventArgs e)
            HttpApplication app = (HttpApplication)source;
            HttpContext context = app.Context;

            // Set a SubStatusCode for Failed Request Tracing in IIS7
            context.Response.SubStatusCode = 99;


Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

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

.NET Framework

Supported in: 3.5 SP1, 3.0 SP1, 2.0 SP1