The Problem Solver

Using the ASP.Net membership provider in a Windows forms application part 4.

In my last three blog entries I showed how to use the ASP.Net membership provider in a Windows application. I finished with the problem of storing the current user name and the fact that there is a second overload to the IsUserInRole() function that only takes a role name. Well it turns out that this function checks for the current user and uses either the HttpContext.Current.User or the Threading.Thread.CurrentPrincipal depending on the fact if the application is hosted. As the Threading.Thread.CurrentPrincipal is the normal way access is provided to the current user and role information in a windows application this seems like the natural thing to do.

The System.Web.Security.RolePrincipal class implements the required IPrincipal interface so this is the class we need to use. To create the required object we need an IIDentity object to provide the user identity information. This can be provided using the System.Security.Principal.GenericIdentity class that implements the IIdentity interface.

Add the following code to the top of the Module1.vb:

Imports System.Security.Principal

Now we can set the principal and check for specific roles using the following code:

        Dim user As MembershipUser = Membership.GetUser("Maurice")
        Dim identity As New GenericIdentity(user.UserName)
        Dim principal As New RolePrincipal(identity)
        Threading.Thread.CurrentPrincipal = principal

        If Roles.IsUserInRole("Developer") Then
            Console.WriteLine("Is a developer.")
        Else
            Console.WriteLine("Doesn't write code.")
        End If

An alternative way of checking the user and role is:

        Console.Write(Threading.Thread.CurrentPrincipal.Identity.Name)
        If Threading.Thread.CurrentPrincipal.IsInRole("Developer") Then
            Console.WriteLine(" is a developer.")
        Else
            Console.WriteLine(" doesn't write code.")
        End If

So the complete console application now looks like:

Imports System.Security.Principal
Imports System.Web.Security

Module Module1
    Sub Main()
        ' Creating a new user
        Dim status As MembershipCreateStatus
        Membership.CreateUser( _
            "Maurice", _
            "Password_1", _
            "maurice@TheProblemSolver.nl", _
            "Password question", _
            "Password answer", _
            True, _
            status)
        ' Check the status for errors
        Console.WriteLine(status.ToString())

        ' Validate a username/password
        If Membership.ValidateUser("Maurice", "Password_1") Then
            Console.WriteLine("User validated.")
        Else
            Console.WriteLine("User invalid!")
        End If
 

        ' Create a new Developer role.
        ' Add the <roleManager enabled="true" /> to the app.config for this to work
        If Not Roles.RoleExists("Developer") Then
            Roles.CreateRole("Developer")
        End If

        ' Add a new role to a known user.
        If Not Roles.IsUserInRole("Maurice", "Developer") Then
            Roles.AddUserToRole("Maurice", "Developer")
        End If

        ' Create a second user with only username/password
        ' Add the <membership><providers> element to the app.config first
        Dim user As MembershipUser
        user = Membership.GetUser("User2")
        If user Is Nothing Then
            user = Membership.CreateUser("User2", "p")
            Console.WriteLine(user.UserName)
        End If

        ' Check is a specified user is in a specific role
        If Roles.IsUserInRole("Maurice", "Developer") Then
            Console.WriteLine("Is a developer.")
        Else
            Console.WriteLine("Doesn't write code.")
        End If 

        ' Set the current application principal information to a known user
        Dim identity As GenericIdentity
        Dim principal As RolePrincipal
        user = Membership.GetUser("Maurice")
        identity = New GenericIdentity(user.UserName)
        principal = New RolePrincipal(identity)
        Threading.Thread.CurrentPrincipal = principal

        ' Check if the current principal is in a specific role
        If Roles.IsUserInRole("Developer") Then
            Console.WriteLine("Is a developer.")
        Else
            Console.WriteLine("Doesn't write code.")
        End If


        ' Set the current application principal information to another known user
        user = Membership.GetUser("User2")
        identity = New GenericIdentity(user.UserName)
        principal = New RolePrincipal(identity)
        Threading.Thread.CurrentPrincipal = principal

        ' Use the principal to check for role information
        Console.Write(Threading.Thread.CurrentPrincipal.Identity.Name)
        If Threading.Thread.CurrentPrincipal.IsInRole("Developer") Then
            Console.WriteLine(" is a developer.")
        Else
            Console.WriteLine(" doesn't write code.")
        End If

        Console.ReadLine()
    End Sub
End Module

 
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <system.web>
    <roleManager enabled="true" />
    <membership
      <providers>
        <remove name="AspNetSqlMembershipProvider"/>
        <add name="AspNetSqlMembershipProvider"
             type="System.Web.Security.SqlMembershipProvider, System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"
             connectionStringName="LocalSqlServer"
             enablePasswordRetrieval="false"
             enablePasswordReset="true"
             requiresQuestionAndAnswer="false"
             applicationName="/"
             requiresUniqueEmail="false"
             passwordFormat="Hashed"
             maxInvalidPasswordAttempts="5"
             minRequiredPasswordLength="1"
             minRequiredNonalphanumericCharacters="0"
             passwordAttemptWindow="10"
             passwordStrengthRegularExpression="" />
      </providers>
    </membership>
  </system.web>
</configuration>
 

Maurice de Beijer
www.TheProblemSolver.nl