checking login credentials to see if they are valid in Active Directory AND check to see if they are apart of a specific group in AD - vb.net

Question

below is a method used to check to see if the Creds entered are good. i also would like to add on to this to see if they are part of group "XXX".
Private Function ValidateActiveDirectoryLogin(ByVal Domain As String, ByVal Username As String, ByVal Password As String) As Boolean
Dim Success As Boolean = False
Dim Entry As New System.DirectoryServices.DirectoryEntry("LDAP://" + Domain, Username, Password)
Dim Searcher As New System.DirectoryServices.DirectorySearcher(Entry)
Searcher.SearchScope = DirectoryServices.SearchScope.OneLevel
Try
Dim Results As System.DirectoryServices.SearchResult = Searcher.FindOne
Success = Not (Results Is Nothing)
Catch ex As Exception
Success = False
End Try
Return Success
End Function
and below i tried to play around with stuff i found on stack but im not having much luck. how can i use existing method and add to it in order to get my results?
Public Function IsInGroup(ByVal UserName As String) As Boolean
'Dim MyIdentity As System.Security.Principal.WindowsIdentity = New WindowsPrincipal(New WindowsIdentity(UserName)) ' System.Security.Principal.WindowsIdentity.GetCurrent()
'Dim userPrincipal = New WindowsPrincipal(New WindowsIdentity(Username))
Dim MyPrincipal As System.Security.Principal.WindowsPrincipal = New WindowsPrincipal(New WindowsIdentity(UserName)) 'New System.Security.Principal.WindowsPrincipal(userPrincipal)
Return MyPrincipal.IsInRole("XXX_YYY")
End Function
Also Tried to do something like this but getting the error i screenshotted.
Public Function IsInGroup(ByVal UserName As String) As Boolean
Dim Result As Boolean
Dim de As New DirectoryEntry("LDAP://AD")
Dim MemberSearcher As New DirectorySearcher
With MemberSearcher
.SearchRoot = de
.Filter = "(&(ObjectClass=Group)(CN=VAL_ITS))"
.PropertiesToLoad.Add("Member")
End With
Dim mySearchResults As SearchResult = MemberSearcher.FindOne()
For Each User In mySearchResults.Properties("Member")
If User = UserName Then
Result = True
Else
Result = False
End If
Next
Return Result
End Function

Answer 1

'Project > Add Reference > System.DirectoryServices.AccountManagement & System.DirectoryServices
Validate using the System.DirectoryServices.AccountManagement namespace
Imports System.DirectoryServices.AccountManagement
Public function validate(username as string, password as string, domain as string)
Dim valid As Boolean = False
Using context As New PrincipalContext(ContextType.Domain, domain)
valid = context.ValidateCredentials(username, password)
End Using
return valid
End Function
Public function checkgroup(domain as string, username as string, groupname as string)
Dim isMember as boolean = false
Dim ctx As New PrincipalContext(ContextType.Domain, domain)
Dim user As UserPrincipal = UserPrincipal.FindByIdentity(ctx, username)
Dim group As GroupPrincipal = GroupPrincipal.FindByIdentity(ctx, groupname)
If user IsNot Nothing Then
If user.IsMemberOf(group) Then
isMember = True
End If
End If
return isMember
End Function