Windows Authentication and SQLRoleProvider MVC3 - asp.net-mvc-3

Question

I have an internet application that connect users with Windows authentication, when the users come to the office and logon onto Windows session (with AD informations) they're automatically logged onto the web application, i used Windows authenticationto achieve this.
So when i use #User.Identity.Nameit show the username. Now if i want to do something with the username like Roles.AddUserToRole(username, "RoleName");it throws an exception The user 'Domain\user' was not found.
My view :
#using (Html.BeginForm("AddToRH", "Account", FormMethod.Post))
{
<div class="form_settings">
<p>
<span>
#User.Identity.Name
#Html.Label("Username") :
</span>
#Html.Editor("username")
</p>
<p style="padding-top: 15px">
<span> </span>
<input type="submit" value="Enregister" class="submit" />
</p>
</div>
}
My controller :
public ActionResult AddToRH(string username) {
string[] roles = Roles.GetAllRoles();
Boolean contains = false;
foreach (string role in roles)
{
if(role.Equals("RoleName")){
contains=true;
}
}
if (!contains) {
Roles.CreateRole("RoleName");
}
Roles.AddUserToRole(username, "RoleName");
return RedirectToAction("Index","Home");
}
My web.config :
<authentication mode="Windows">
</authentication>
<membership defaultProvider="DefaultMembershipProvider">
<providers>
<add name="DefaultMembershipProvider" type="System.Web.Providers.DefaultMembershipProvider, System.Web.Providers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" connectionStringName="DefaultConnection" enablePasswordRetrieval="false" enablePasswordReset="true" requiresQuestionAndAnswer="false" requiresUniqueEmail="false" maxInvalidPasswordAttempts="5" minRequiredPasswordLength="6" minRequiredNonalphanumericCharacters="0" passwordAttemptWindow="10" applicationName="/"/>
</providers>
</membership>

Answer 1

The mistake was in the provider of membership.
The type:
System.Web.Providers.DefaultMembershipProvider, System.Web.Providers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" connectionStringName="DefaultConnection" enablePasswordRetrieval="false" enablePasswordReset="true" requiresQuestionAndAnswer="false" requiresUniqueEmail="false" maxInvalidPasswordAttempts="5" minRequiredPasswordLength="6" minRequiredNonalphanumericCharacters="0" passwordAttemptWindow="10" applicationName="/"`
is generated by default with the project and don't use the dbo.aspnet_X table. This is why in my opinion i can't retrieve the user.
This is an article that helped me a lot:
http://weblogs.asp.net/scottgu/pages/Recipe_3A00_-Implementing-Role_2D00_Based-Security-with-ASP.NET-2.0-using-Windows-Authentication-and-SQL-Server.aspx
Change also the other provider : For Roles i used SQLRoleProvider so the type is : System.Web.Security.SqlRoleProviderand for the Profile i used : type="System.Web.Security.SqlProfileProvider"