friendly error page in asp.net mvc

Question

I have just installed ELMAH on my asp.net mvc application, this framework logs all errors and I can see the logs friendly on a page /elmah

This is exactly what I need, but I need to do something else

1. If an exception is thrown by any reason, I want to show a friendly page
2. The exception must still be caught by elmah

What am I missing to configure?

<?xml version="1.0" encoding="utf-8"?>
<!--
  For more information on how to configure your ASP.NET application, please visit
  http://go.microsoft.com/fwlink/?LinkId=301880
  -->
<configuration>
  <configSections>
    <sectionGroup name="elmah">
      <section name="security" requirePermission="false" type="Elmah.SecuritySectionHandler, Elmah" />
      <section name="errorLog" requirePermission="false" type="Elmah.ErrorLogSectionHandler, Elmah" />
      <section name="errorMail" requirePermission="false" type="Elmah.ErrorMailSectionHandler, Elmah" />
      <section name="errorFilter" requirePermission="false" type="Elmah.ErrorFilterSectionHandler, Elmah" />
    </sectionGroup>
  </configSections>
  <appSettings>
    <add key="webpages:Version" value="3.0.0.0" />
    <add key="webpages:Enabled" value="false" />
    <add key="ClientValidationEnabled" value="true" />
    <add key="UnobtrusiveJavaScriptEnabled" value="true" />
    <add key="ClientId" value="ss" />
    <add key="ClientSecret" value="xx" />
    <add key="elmah.mvc.disableHandler" value="false" />
    <add key="elmah.mvc.disableHandleErrorFilter" value="false" />
    <add key="elmah.mvc.requiresAuthentication" value="false" />
    <add key="elmah.mvc.IgnoreDefaultRoute" value="false" />
    <add key="elmah.mvc.allowedRoles" value="*" />
    <add key="elmah.mvc.allowedUsers" value="*" />
    <add key="elmah.mvc.route" value="elmah" />
  </appSettings>
  <system.web>
    <httpHandlers>
      <add verb="POST,GET,HEAD" path="elmah.axd" type="Elmah.ErrorLogPageFactory, Elmah" />
    </httpHandlers>
    <compilation debug="true" targetFramework="4.5" />
    <httpRuntime targetFramework="4.5" />
    <httpModules>
      <add name="ErrorLog" type="Elmah.ErrorLogModule, Elmah" />
      <add name="ErrorMail" type="Elmah.ErrorMailModule, Elmah" />
      <add name="ErrorFilter" type="Elmah.ErrorFilterModule, Elmah" />
    </httpModules>
  </system.web>
  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Helpers" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-3.0.0.0" newVersion="3.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Mvc" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="0.0.0.0-5.0.0.0" newVersion="5.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Optimization" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-1.1.0.0" newVersion="1.1.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.WebPages" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-3.0.0.0" newVersion="3.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="WebGrease" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="0.0.0.0-1.5.2.14234" newVersion="1.5.2.14234" />
      </dependentAssembly>
    </assemblyBinding>
  </runtime>
  <system.serviceModel>
    <bindings>
      <basicHttpBinding>
        <!--Used by app for SharePoint-->
        <binding name="secureBinding">
          <security mode="Transport" />
        </binding>
      </basicHttpBinding>
    </bindings>
    <protocolMapping>
      <add binding="basicHttpBinding" scheme="https" bindingConfiguration="secureBinding" />
    </protocolMapping>
  </system.serviceModel>
  <system.webServer>
    <validation validateIntegratedModeConfiguration="false" />
    <modules>
      <add name="ErrorLog" type="Elmah.ErrorLogModule, Elmah" preCondition="managedHandler" />
      <add name="ErrorMail" type="Elmah.ErrorMailModule, Elmah" preCondition="managedHandler" />
      <add name="ErrorFilter" type="Elmah.ErrorFilterModule, Elmah" preCondition="managedHandler" />
    </modules>
  </system.webServer>
  <elmah>
    <errorLog type="Elmah.XmlFileErrorLog, Elmah" logPath="~/App_Data" />
  </elmah>
</configuration>

Answer 1

You are missing the customErrors section:

<system.web>
  <customErrors defaultRedirect="~/error" mode="RemoteOnly"/>
</system.web>

This will redirect the user to http://example.org/error URL when an exception is unhandled. You can show a user friendly page by writing an action method that would respond to this URL or you can use a static file. ELMAH will still log the exception.