法蘭克不要怕

using System.DirectoryServices.AccountManagement;

PrincipalContext ctx = new PrincipalContext(ContextType.Domain);

UserPrincipal qbeUser = new UserPrincipal(ctx);

PrincipalSearcher srch = new PrincipalSearcher(qbeUser);

List<string> ADUser = new List<string>();

foreach (var found in srch.FindAll())

{

UserPrincipal user = found as UserPrincipal;

if (user != null)

{

ADUser.Add(user.DisplayName + "," + user.Sid.ToString());

}
}

============================================

public bool CheckPassword(string userName, string password)
{
            PrincipalContext adContext = new PrincipalContext(ContextType.Domain);
            return adContext.ValidateCredentials(userName, password);
}