Function Test-UserCredential {

   [CmdletBinding()] [OutputType([System.Boolean])]

   param(

     [Parameter(Mandatory=$true)] [ValidateNotNullOrEmpty()]

     [System.String] $Username,




     [Parameter(Mandatory=$true)] [ValidateNotNullOrEmpty()]

     [System.String] $Password,

    

     [Parameter()]

     [Switch] $Domain

   )

  

   Begin {

     $assembly = [system.reflection.assembly]::LoadWithPartialName('System.DirectoryServices.AccountManagement')

   }

  

   Process {

     try {

       $system = Get-WmiObject -Class Win32_ComputerSystem

       if ($Domain) {

         if (0, 2 -contains $system.DomainRole) {

           throw 'This computer is not a member of a domain.'

         } else {

           $principalContext = New-Object -TypeName System.DirectoryServices.AccountManagement.PrincipalContext 'Domain', $system.Domain

         }

       } else {

         $principalContext = New-Object -TypeName System.DirectoryServices.AccountManagement.PrincipalContext 'Machine', $env:COMPUTERNAME

       }

      

       return $principalContext.ValidateCredentials($Username, $Password)

     }

     catch {

       throw 'Failed to test user credentials. The error was: "{0}".' -f $_

     }

   }

}