ASP.NET MVC 3.0 Application Template CAPTCHA VB.NET Code Example

The ASP.NET MVC 3.0 application template Captcha example project shows how to use the BotDetect CAPTCHA MvcCaptcha control in ASP.NET MVC web applications.

First Time Here?

Check the BotDetect ASP.NET MVC Captcha Quickstart for key integration steps.

Starting with the default ASP.NET MVC 3.0 Visual Studio 2010 project template, the example includes all code required to add CAPTCHA validation to the Account controller Register action.

The example remembers when the CAPTCHA is successfully solved within a single registration, and doesn't display it again if there are errors with other form values (the username, for example).

You can get a new CAPTCHA using the Register action link in the top right corner of the page, and see the explanation in the Account controller code.

Download the BotDetect ASP.NET CAPTCHA Component and run this example

→ ASP.NET MVC version:

→ .NET programming language:

  • C#
  • VB.NET

Installed Location

By default, the .NET 4.0 VB.NET version of the ASP.NET MVC 3.0 application template Captcha example project is installed at:
C:\Program Files\Captcha Inc\BotDetect 4 CAPTCHA Component\Asp.Net\.NET\WebApp\TraditionalAPI\Mvc30CaptchaExample\VBNet

You can also run it from the BotDetect Start Menu:
Programs > Captcha Inc > BotDetect 4 CAPTCHA Component > ASP.NET > ASP.NET Examples > Run .NET Examples

Models\AccountModels.vb

Imports System.ComponentModel 
Imports System.ComponentModel.DataAnnotations 
Imports System.Globalization 

Public Class ChangePasswordModel 
  Private oldPasswordValue As String 
  Private newPasswordValue As String 
  Private confirmPasswordValue As String 

  <Required()> _ 
  <DataType(DataType.Password)> _ 
  <Display(Name:="Current password")> _ 
  Public Property OldPassword() As String 
    Get 
      Return oldPasswordValue 
    End Get 
    Set(ByVal value As String) 
      oldPasswordValue = value 
    End Set 
  End Property 

  <Required()> _ 
  <StringLength(100, 
  ErrorMessage:="The {0} must be at least {2} characters long.", 
  MinimumLength:=6)> _ 
  <DataType(DataType.Password)> _ 
  <Display(Name:="New password")> _ 
  Public Property NewPassword() As String 
    Get 
      Return newPasswordValue 
    End Get 
    Set(ByVal value As String) 
      newPasswordValue = value 
    End Set 
  End Property 

  <DataType(DataType.Password)> _ 
  <Display(Name:="Confirm new password")> _ 
  <Compare("NewPassword", 
  ErrorMessage:="The new password and confirmation password do not match.")> _ 
  Public Property ConfirmPassword() As String 
    Get 
      Return confirmPasswordValue 
    End Get 
    Set(ByVal value As String) 
      confirmPasswordValue = value 
    End Set 
  End Property 
End Class 

Public Class LogOnModel 
  Private userNameValue As String 
  Private passwordValue As String 
  Private rememberMeValue As Boolean 

  <Required()> _ 
  <Display(Name:="User name")> _ 
  Public Property UserName() As String 
    Get 
      Return userNameValue 
    End Get 
    Set(ByVal value As String) 
      userNameValue = value 
    End Set 
  End Property 

  <Required()> _ 
  <DataType(DataType.Password)> _ 
  <Display(Name:="Password")> _ 
  Public Property Password() As String 
    Get 
      Return passwordValue 
    End Get 
    Set(ByVal value As String) 
      passwordValue = value 
    End Set 
  End Property 

  <Display(Name:="Remember me?")> _ 
  Public Property RememberMe() As Boolean 
    Get 
      Return rememberMeValue 
    End Get 
    Set(ByVal value As Boolean) 
      rememberMeValue = value 
    End Set 
  End Property 
End Class 

Public Class RegisterModel 
  Private userNameValue As String 
  Private passwordValue As String 
  Private confirmPasswordValue As String 
  Private emailValue As String 

  <Required()> _ 
  <Display(Name:="User name")> _ 
  Public Property UserName() As String 
    Get 
      Return userNameValue 
    End Get 
    Set(ByVal value As String) 
      userNameValue = value 
    End Set 
  End Property 

  <Required()> _ 
  <DataType(DataType.EmailAddress)> _ 
  <Display(Name:="Email address")> _ 
  Public Property Email() As String 
    Get 
      Return emailValue 
    End Get 
    Set(ByVal value As String) 
      emailValue = value 
    End Set 
  End Property 

  <Required()> _ 
  <StringLength(100, 
  ErrorMessage:="The {0} must be at least {2} characters long.", 
  MinimumLength:=6)> _ 
  <DataType(DataType.Password)> _ 
  <Display(Name:="Password")> _ 
  Public Property Password() As String 
    Get 
      Return passwordValue 
    End Get 
    Set(ByVal value As String) 
      passwordValue = value 
    End Set 
  End Property 

  <DataType(DataType.Password)> _ 
  <Display(Name:="Confirm password")> _ 
  <Compare("Password", 
  ErrorMessage:="The password and confirmation password do not match.")> _ 
  Public Property ConfirmPassword() As String 
    Get 
      Return confirmPasswordValue 
    End Get 
    Set(ByVal value As String) 
      confirmPasswordValue = value 
    End Set 
  End Property 

  ' add Captcha code as a field in the protected action Model 
  Private captchaCodeValue As String 

  <Required(ErrorMessage:="Retyping the characters from the picture is required.  ")> _ 
  <DisplayName("Please retype the characters from the picture")> _ 
  Public Property CaptchaCode() As String 
    Get 
      Return captchaCodeValue 
    End Get 
    Set(ByVal value As String) 
      captchaCodeValue = value 
    End Set 
  End Property 
End Class 

Since we want to include Captcha validation in the Register action, we add a string field representing the Captcha code to the related RegisterModel class declaration.

The <Required> attribute specifies that the Captcha code input field cannot be left blank (and which error message to display if it is), while the <Display> attribute declares the text description used to prompt users to type the Captcha code.

Views\Account\Register.vbhtml

@ModelType AspNetMvc30CaptchaExampleVBNet.RegisterModel 
@Imports BotDetect.Web.Mvc 
@Imports AspNetMvc30CaptchaExampleVBNet 
@Code 
  ViewData("Title") = "Register" 
End Code 
@* add BotDetect header includes *@ 
@Section BotDetectStyles 
  <link href="@BotDetect.Web.CaptchaUrls.Absolute.LayoutStyleSheetUrl" 
  rel="stylesheet" type="text/css" /> 
End Section 
<h2> 
  Create a New Account</h2> 
<p> 
  Use the form below to create a new account. 
</p> 
<p> 
  Passwords are required to be a minimum of @Membership. 
  MinRequiredPasswordLength 
  characters in length. 
</p> 
<script src="@Url.Content("~/Scripts/jquery.validate.min.js")" 
type="text/javascript"></script> 
<script src="@Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")" 
type="text/javascript"></script> 
@Using Html.BeginForm("Register", "Account") 
  @Html.ValidationSummary(True, 
  "Account creation was unsuccessful. Please correct the errors and try again.") 
  @<div> 
    <fieldset> 
      <legend>Account Information</legend> 
      <div class="editor-label"> 
        @Html.LabelFor(Function(m) m.UserName) 
      </div> 
      <div class="editor-field"> 
        @Html.TextBoxFor(Function(m) m.UserName) 
        @Html.ValidationMessageFor(Function(m) m.UserName) 
      </div> 
      <div class="editor-label"> 
        @Html.LabelFor(Function(m) m.Email) 
      </div> 
      <div class="editor-field"> 
        @Html.TextBoxFor(Function(m) m.Email) 
        @Html.ValidationMessageFor(Function(m) m.Email) 
      </div> 
      <div class="editor-label"> 
        @Html.LabelFor(Function(m) m.Password) 
      </div> 
      <div class="editor-field"> 
        @Html.PasswordFor(Function(m) m.Password) 
        @Html.ValidationMessageFor(Function(m) m.Password) 
      </div> 
      <div class="editor-label"> 
        @Html.LabelFor(Function(m) m.ConfirmPassword) 
      </div> 
      <div class="editor-field"> 
        @Html.PasswordFor(Function(m) m.ConfirmPassword) 
        @Html.ValidationMessageFor(Function(m) m.ConfirmPassword) 
      </div> 
      @* add Captcha validation controls to the protected action View *@ 
      @Code Dim registrationCaptcha As MvcCaptcha 
        registrationCaptcha = CaptchaHelper.GetRegistrationCaptcha() 
      End Code 
      @If (Not registrationCaptcha.IsSolved) Then 
      @:<div class="editor-label"> 
        @Html.LabelFor(Function(m) m.CaptchaCode) 
        @Html.Captcha(registrationCaptcha) 
      @:</div>             
      @:<divclass="editor-field"> 
        @Html.TextBoxFor(Function(m) m.CaptchaCode) 
        @Html.ValidationMessageFor(Function(m) m.CaptchaCode) 
      @:</div> 
      End If 
      <p style="width: 210px; text-align: right;"> 
        <input type="submit" value="Register" /> 
      </p> 
    </fieldset> 
  </div> 
End Using 

Following ASP.NET MVC 3.0 Captcha View instructions, the BotDetectStyles section includes required BotDetect stylesheets in the generated page header.

To keep View code simple, we delegate MvcCaptcha instance creation to a helper class, and use it along with Model fields to generate the required markup using straightforward HtmlHelper calls.

Since we want to avoid re-displaying the Captcha challenge to users after they solve it, we only call the markup generation code if the IsSolved property is not set by a previous successful Captcha validation.

Views\Shared\_Layout.vbhtml

<!DOCTYPE html> 
<html> 
<head> 
  <meta charset="utf-8" /> 
  <title>@ViewData("Title")</title> 
  <link href="@Url.Content("~/Content/Site.css")" rel="stylesheet" 
  type="text/css" /> 
  <script src="@Url.Content("~/Scripts/jquery-1.5.1.min.js")" 
  type="text/javascript"></script> 
  <script src="@Url.Content("~/Scripts/modernizr-1.7.min.js")" 
  type="text/javascript"></script> 
  @* allow BotDetect stylesheet includes in selected Views *@ 
  @RenderSection("BotDetectStyles", required:=False) 
</head> 
<body> 
  <div class="page"> 
    <header> 
            <div id="title"> 
                <h1>BotDetect CAPTCHA ASP.NET MVC 3.0 Example</h1> 
            </div> 
            <div id="logindisplay"> 
                @Html.Partial("_LogOnPartial") 
            </div> 
            <nav> 
                <ul id="menu"> 
                    <li>@Html.ActionLink("Home", "Index", "Home")</li> 
                    <li>@Html.ActionLink("About", "About", "Home")</li> 
                </ul> 
            </nav> 
        </header> 
    <section id="main"> 
            @RenderBody() 
        </section> 
    <footer> 
        </footer> 
  </div> 
</body> 
</html> 

To allow easy inclusion of BotDetect stylesheets into Views which require them, the BotDetectStyles section was declared in the layout template header.

Controllers\AccountController.vb

Imports System.Diagnostics.CodeAnalysis 
Imports System.Security.Principal 
Imports System.Web.Routing 
Imports BotDetect.Web.Mvc 

Public Class AccountController 
  Inherits System.Web.Mvc.Controller 

  ' 
  ' GET: /Account/LogOn 

  Public Function LogOn() As ActionResult 
    Return View() 
  End Function 

  ' 
  ' POST: /Account/LogOn 

  <HttpPost()> _ 
  Public Function LogOn(ByVal model As LogOnModel, ByVal returnUrl As String) As 
  ActionResult 
    If ModelState.IsValid Then 
      If Membership.ValidateUser(model.UserName, model.Password) Then 
        FormsAuthentication.SetAuthCookie(model.UserName, model.RememberMe) 
        If Url.IsLocalUrl(returnUrl) AndAlso returnUrl.Length > 1 AndAlso 
        returnUrl.StartsWith("/") _ 
           AndAlso Not returnUrl.StartsWith("//") 
           AndAlso Not returnUrl.StartsWith("/\\") 
        Then 
          Return Redirect(returnUrl) 
        Else 
          Return RedirectToAction("Index", "Home") 
        End If 
      Else 
        ModelState.AddModelError("", "The user name or password provided is  
        incorrect.") 
      End If 
    End If 

    ' If we got this far, something failed, redisplay form 
    Return View(model) 
  End Function 

  ' 
  ' GET: /Account/LogOff 

  Public Function LogOff() As ActionResult 
    FormsAuthentication.SignOut() 

    Return RedirectToAction("Index", "Home") 
  End Function 

  ' 
  ' GET: /Account/Register 
  Public Function Register() As ActionResult 

    ' when the View is accessed directly and not posted, we clear any 
    ' remembered CAPTCHA solving state.  
    ' The users only have to solve the CAPTCHA once within a single  
    ' registration, but if they reload the Register page later, 
    ' it is shown again.  
    ' Otherwise, they could register an unlimited number of accounts  
    ' within a single Session after solving the CAPTCHA only once. 
    MvcCaptcha.ResetCaptcha("RegistrationCaptcha") 

    Return View() 
  End Function 

  ' 
  ' POST: /Account/Register 

  <HttpPost()> _ 
  <CaptchaValidation("CaptchaCode", "RegistrationCaptcha", 
  "Your input doesn't match displayed characters.")> _ 
  Public Function Register(ByVal model As RegisterModel) As ActionResult 
    If ModelState.IsValid Then 
      ' Attempt to register the user 
      Dim createStatus As MembershipCreateStatus 
      Membership.CreateUser(model.UserName, model.Password, model.Email, Nothing, 
      Nothing, True, Nothing, createStatus) 

      If createStatus = MembershipCreateStatus.Success Then 
        FormsAuthentication.SetAuthCookie(model.UserName, False) 
        Return RedirectToAction("Index", "Home") 
      Else 
        ModelState.AddModelError("", ErrorCodeToString(createStatus)) 
      End If 
    End If 

    ' If we got this far, something failed, redisplay form 
    Return View(model) 
  End Function 

  ' 
  ' GET: /Account/ChangePassword 

  <Authorize()> _ 
  Public Function ChangePassword() As ActionResult 
    Return View() 
  End Function 

  ' 
  ' POST: /Account/ChangePassword 

  <Authorize()> _ 
  <HttpPost()> _ 
  Public Function ChangePassword(ByVal model As ChangePasswordModel) As 
  ActionResult 
    If ModelState.IsValid Then 
      ' ChangePassword will throw an exception rather 
      ' than return false in certain failure scenarios. 
      Dim changePasswordSucceeded As Boolean 

      Try 
        Dim currentUser As MembershipUser = Membership.GetUser(User.Identity.Name, 
        True) 
        changePasswordSucceeded = currentUser.ChangePassword(model.OldPassword, 
        model.NewPassword) 
      Catch ex As Exception 
        changePasswordSucceeded = False 
      End Try 

      If changePasswordSucceeded Then 
        Return RedirectToAction("ChangePasswordSuccess") 
      Else 
        ModelState.AddModelError("", 
        "The current password is incorrect or the new password is invalid.") 
      End If 
    End If 

    ' If we got this far, something failed, redisplay form 
    Return View(model) 
  End Function 

  ' 
  ' GET: /Account/ChangePasswordSuccess 

  Public Function ChangePasswordSuccess() As ActionResult 
    Return View() 
  End Function 

#Region "Status Code" 
  Public Function ErrorCodeToString(ByVal createStatus As MembershipCreateStatus) 
  As String 
    ' See http://go.microsoft.com/fwlink/?LinkID=177550 for 
    ' a full list of status codes. 
    Select Case createStatus 
      Case MembershipCreateStatus.DuplicateUserName 
        Return "User name already exists. Please enter a different user name." 

      Case MembershipCreateStatus.DuplicateEmail 
        Return "A user name for that e-mail address already exists. Please enter  
        a different e-mail address." 

      Case MembershipCreateStatus.InvalidPassword 
        Return "The password provided is invalid. Please enter a valid password  
        value." 

      Case MembershipCreateStatus.InvalidEmail 
        Return "The e-mail address provided is invalid. Please check the value  
        and try again." 

      Case MembershipCreateStatus.InvalidAnswer 
        Return "The password retrieval answer provided is invalid. Please check  
        the value and try again." 

      Case MembershipCreateStatus.InvalidQuestion 
        Return "The password retrieval question provided is invalid. Please  
        check the value and try again." 

      Case MembershipCreateStatus.InvalidUserName 
        Return "The user name provided is invalid. Please check the value and  
        try again." 

      Case MembershipCreateStatus.ProviderError 
        Return "The authentication provider returned an error. Please verify  
        your entry and try again. If the problem persists, please contact your  
        system administrator." 

      Case MembershipCreateStatus.UserRejected 
        Return "The user creation request has been canceled. Please verify your  
        entry and try again. If the problem persists, please contact your system  
        administrator." 

      Case Else 
        Return "An unknown error occurred. Please verify your entry and try  
        again. If the problem persists, please contact your system administrator. 
        " 
    End Select 
  End Function 
#End Region 

End Class 

To add Captcha validation to the Register action Controller code, we perform a single line of setup in the Register action when the user GETs it, and execute the <CaptchaValidation> filter when the user POSTs it.

The filter attribute will automatically add the appropriate ModelState error if the Captcha code input doesn't match the code displayed to the user in the Captcha picture.

CaptchaHelper.vb

Imports BotDetect 
Imports BotDetect.Web 
Imports BotDetect.Web.UI 
Imports BotDetect.Web.Mvc 

Public Class CaptchaHelper 

  Public Shared Function GetRegistrationCaptcha() As MvcCaptcha 

    ' create the control instance 
    Dim registrationCaptcha As BotDetect.Web.Mvc.MvcCaptcha = _ 
        New BotDetect.Web.Mvc.MvcCaptcha("RegistrationCaptcha") 

    registrationCaptcha.UserInputID = "CaptchaCode" 

    ' all Captcha properties are set in this event handler 
    AddHandler WebFormsCaptcha.InitializedWebCaptcha, _ 
        AddressOf RegistrationCaptcha_InitializedWebCaptcha 

    Return registrationCaptcha 

  End Function 

  ' event handler used for Captcha control property randomization 
  Public Shared Sub RegistrationCaptcha_InitializedWebCaptcha( _ 
      ByVal sender As Object, _ 
      ByVal e As BotDetect.InitializedWebCaptchaEventArgs) 

    If (e.CaptchaId <> "RegistrationCaptcha") Then 
      Return 
    End If 

    Dim registrationCaptcha As Captcha = TryCast(sender, Captcha) 

    ' fixed Captcha settings  
    registrationCaptcha.ImageSize = New System.Drawing.Size(200, 50) 
    registrationCaptcha.CodeLength = 4 

    ' randomized Captcha settings 
    registrationCaptcha.ImageStyle = CaptchaRandomization.GetRandomImageStyle() 
    registrationCaptcha.SoundStyle = CaptchaRandomization.GetRandomSoundStyle() 
  End Sub 

End Class 

Captcha instance creation and property setting is encapsulated in this simple helper class. This separation allows application Views to stay simple regardless of the amount of Captcha customization chosen.

Global.asax.vb

' Note: For instructions on enabling IIS6 or IIS7 classic mode,  
' visit http://go.microsoft.com/?LinkId=9394802 

Public Class MvcApplication 
  Inherits System.Web.HttpApplication 

  Shared Sub RegisterGlobalFilters(ByVal filters As GlobalFilterCollection) 
    filters.Add(New HandleErrorAttribute()) 
  End Sub 

  Shared Sub RegisterRoutes(ByVal routes As RouteCollection) 
    routes.IgnoreRoute("{resource}.axd/{*pathInfo}") 

    ' BotDetect requests must not be routed 
    routes.IgnoreRoute("{*botdetect}", 
    New With {.botdetect = "(.*)BotDetectCaptcha\.ashx"}) 

    ' MapRoute takes the following parameters, in order: 
    ' (1) Route name 
    ' (2) URL with parameters 
    ' (3) Parameter defaults 
    routes.MapRoute( _ 
        "Default", _ 
        "{controller}/{action}/{id}", _ 
        New With {.controller = "Account", .action = "Register", . 
        id = UrlParameter.Optional} _ 
    ) 

  End Sub 

  Sub Application_Start() 
    AreaRegistration.RegisterAllAreas() 

    RegisterGlobalFilters(GlobalFilters.Filters) 
    RegisterRoutes(RouteTable.Routes) 
  End Sub 
End Class 

Since all BotDetect requests are handled by the BotDetect HttpHandler, ASP.NET Url Routing must be configured to ignore BotDetect requests, which can be achieved by a single line of code in Global.asax code-behind.

Web.config

<?xml version="1.0"?> 
<!-- 
  For more information on how to configure your ASP.NET application, please  
  visit 
  http://go.microsoft.com/fwlink/?LinkId=152368 
  --> 

<configuration> 
  <configSections> 
    <!-- Register the BotDetect configuration section --> 
    <section name="botDetect" requirePermission="false" 
    type="BotDetect.Configuration.BotDetectConfigurationSection, BotDetect"/> 
  </configSections> 
  <connectionStrings> 
    <add name="ApplicationServices" 
         connectionString="data source=.\SQLEXPRESS;Integrated Security=SSPI; 
         AttachDBFilename=|DataDirectory|aspnetdb.mdf;User Instance=true" 
         providerName="System.Data.SqlClient" /> 
  </connectionStrings> 
  <appSettings> 
    <add key="webpages:Version" value="1.0.0.0"/> 
    <add key="ClientValidationEnabled" value="true"/> 
    <add key="UnobtrusiveJavaScriptEnabled" value="true"/> 
  </appSettings> 
  <system.web> 
    <compilation debug="true" targetFramework="4.0"> 
      <assemblies> 
        <add assembly="System.Web.Abstractions, Version=4.0.0.0, Culture=neutral, 
        PublicKeyToken=31BF3856AD364E35" /> 
        <add assembly="System.Web.Routing, Version=4.0.0.0, Culture=neutral,  
        PublicKeyToken=31BF3856AD364E35" /> 
        <add assembly="System.Web.Mvc, Version=3.0.0.0, Culture=neutral,  
        PublicKeyToken=31BF3856AD364E35" /> 
        <add assembly="System.Web.WebPages, Version=1.0.0.0, Culture=neutral,  
        PublicKeyToken=31BF3856AD364E35" /> 
      </assemblies> 
    </compilation> 
    <authentication mode="Forms"> 
      <forms loginUrl="~/Account/LogOn" timeout="2880" /> 
    </authentication> 
    <membership> 
      <providers> 
        <clear/> 
        <add name="AspNetSqlMembershipProvider" type="System.Web.Security. 
        SqlMembershipProvider" connectionStringName="ApplicationServices" 
             enablePasswordRetrieval="false" enablePasswordReset="true" 
             requiresQuestionAndAnswer="false" requiresUniqueEmail="false" 
             maxInvalidPasswordAttempts="5" minRequiredPasswordLength="6" 
             minRequiredNonalphanumericCharacters="0" 
             passwordAttemptWindow="10" 
             applicationName="/" /> 
      </providers> 
    </membership> 
    <profile> 
      <providers> 
        <clear/> 
        <add name="AspNetSqlProfileProvider" type="System.Web.Profile. 
        SqlProfileProvider" connectionStringName="ApplicationServices" 
        applicationName="/" /> 
      </providers> 
    </profile> 
    <roleManager enabled="false"> 
      <providers> 
        <clear/> 
        <add name="AspNetSqlRoleProvider" type="System.Web.Security. 
        SqlRoleProvider" connectionStringName="ApplicationServices" 
        applicationName="/" /> 
        <add name="AspNetWindowsTokenRoleProvider" type="System.Web.Security. 
        WindowsTokenRoleProvider" applicationName="/" /> 
      </providers> 
    </roleManager> 
    <!-- make sure Session State is enabled --> 
    <pages enableSessionState="true"> 
      <namespaces> 
        <add namespace="System.Web.Mvc" /> 
        <add namespace="System.Web.Mvc.Ajax" /> 
        <add namespace="System.Web.Mvc.Html" /> 
        <add namespace="System.Web.Routing" /> 
        <add namespace="System.Web.WebPages" /> 
      </namespaces> 
    </pages> 
    <!-- configure Session State for BotDetect use --> 
    <sessionState mode="InProc" cookieless="AutoDetect" timeout="20" 
    sessionIDManagerType="BotDetect.Web.CustomSessionIdManager, BotDetect"/> 
    <httpHandlers> 
      <!-- register HttpHandler used for BotDetect Captcha requests --> 
      <add verb="GET" path="BotDetectCaptcha.ashx" 
      type="BotDetect.Web.CaptchaHandler, BotDetect"/> 
    </httpHandlers> 
  </system.web> 
  <system.webServer> 
    <validation validateIntegratedModeConfiguration="false"/> 
    <modules runAllManagedModulesForAllRequests="true"/> 
    <handlers> 
      <!-- register HttpHandler used for BotDetect Captcha requests --> 
      <remove name="BotDetectCaptchaHandler"/> 
      <add name="BotDetectCaptchaHandler" preCondition="integratedMode" 
      verb="GET" path="BotDetectCaptcha.ashx" 
      type="BotDetect.Web.CaptchaHandler, BotDetect"/> 
    </handlers> 
  </system.webServer> 
  <runtime> 
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1"> 
      <dependentAssembly> 
        <assemblyIdentity name="System.Web.Mvc" 
        publicKeyToken="31bf3856ad364e35" /> 
        <bindingRedirect oldVersion="1.0.0.0-2.0.0.0" newVersion="3.0.0.0" /> 
      </dependentAssembly> 
    </assemblyBinding> 
  </runtime> 
  <botDetect helpLinkEnabled="true" helpLinkMode="image"/> 
</configuration> 

The application's web.config file includes the standard BotDetect HttpHandler and Session state configuration elements.