.NET: Using AD to change a users Password and get Password expiry date

1. Add reference to ActiveDS.tlb (still most AD interfaces are in COM)

2. Following is code from a lot of online sites merged/tested together for a complete working solution.

Building Secure ASP.NET Applications: Authentication, Authorization, and Secure Communication

http://www.15seconds.com/issue/020730.htm

http://directoryprogramming.net/forums/thread/1531.aspx

Use RoleManager for Windows Authentication in ASP.NET 2.0

// Set the search string along with LDAP path. The search is on username.

// You shouldn't bind as the user whose password you want to change, hence use impersonatable-known-user

string path =
"LDAP://"+"ldapserver"+"/CN="+"username-to-test"+"," + "CN=Users,DC=domain1,DC=main-domain";
try
{
         // Create a 'DirectoryEntry' object to search
         DirectoryEntry entry = new DirectoryEntry(path, "impersonatable-known-user", "impersonate-known-password",
                                AuthenticationTypes.ServerBind);
         //OR DirectoryEntry entry = new DirectoryEntry(path, domain + "\\" +
                        impersonatable-known-user, impersonate-known-password,
         //AuthenticationTypes.Secure);

         Object obj = null;
         try
         {
             //Bind to the native AdsObject to force authentication.
             Object obj = entry.NativeObject;
         }
         catch (Exception ex)
         {
             throw new Exception("Error authenticating user. " + ex.Message);
         }

         if (!obj)
         {
              //user is not authenicated
              return false;
         }
         //user is authenicated

         // Create the Directory search instance.
         DirectorySearcher search = new DirectorySearcher(entry);

        //maybe this line is better --> DirectoryEntry result = new DirectoryEntry(path,
               //  null, null, AuthenticationTypes.None) 'Bind using existing, open connection

        // Get the first search result - search is on username.
        SearchResult result = search.FindOne();
        // If the username has been found in the LDAP server.

        if(null != result)
        {
          // The result obtained will look like the following:
          // CN=group1,CN=group2,DC=domain1,DC=main-domain
          // Get the value of 'memberof' from the properties collection
          //MSDN Sample: 'System.DirectoryServices.SearchResult'
          if (result.Properties.Contains("memberof"))
          {
.....