How to Query User Information From Active Directory in C#

using System;
using System.Text;
using System.DirectoryServices;

namespace queryInfoAD {

  class userActiveDirectory {
    static void Main(string[] args) {
      // Input the user name (password can also be required) to get a particular user info from
      // Active Directory

      Console.Write("User Name = ");
      String searchUsername = Console.ReadLine();

      try {
        // create an LDAP connection object that will help you fetch the Active Directory user

        DirectoryEntry userLdapConn = createDirectoryEntry();

        // create `ObjSearch` as a search object which operates on an LDAP connection object to only
        // find a single user's details

        DirectorySearcher ObjSearch = new DirectorySearcher(userLdapConn);
        ObjSearch.Filter = searchUsername;

        // create result objects from the search object

        SearchResult checkUser = ObjSearch.FindOne();

        if (checkUser != null) {
          ResultPropertyCollection fields = checkUser.Properties;

          foreach (String ldapUser in fields.PropertyNames) {
            foreach (Object InfoChart in fields[ldapUser])
              Console.WriteLine(String.Format("{0,-20} : {1}", ldapUser, InfoChart.ToString()));
          }
        }

        else {
          Console.WriteLine("User does not exist!");
        }
      }

      catch (Exception e) {
        Console.WriteLine("Error!\n\n" + e.ToString());
      }
    }

    static DirectoryEntry createDirectoryEntry() {
      // create an LDAP connection with custom settings and return it

      DirectoryEntry ldapConnection = new DirectoryEntry("Insert connection domain link...");
      ldapConnection.Path =
          "Insert the path to the Active Directory which contains user information";
      ldapConnection.AuthenticationType = AuthenticationTypes.Secure;

      return ldapConnection;
    }
  }
}

using System;
using System.DirectoryServices;
using System.DirectoryServices.AccountManagement;

// add the reference in the `System.DirectoryServices.AccountManagement` library to your project
// before executing this code

namespace DSAM_examp {
  class AccManagement {
    static void Main(string[] args) {
      try {
        // enter Active Directory settings
        PrincipalContext ActiveDirectoryUser =
            new PrincipalContext(ContextType.Domain, "Insert the domain link here...");

        // create search user and add criteria

        Console.Write("Enter User Name: ");
        UserPrincipal userName = new UserPrincipal(ActiveDirectoryUser);
        userName.SamAccountName = Console.ReadLine();

        PrincipalSearcher search = new PrincipalSearcher(userName);

        foreach (UserPrincipal result in search.FindAll())

          // the user information in AD contains the VoiceTelephoneNumber that is unique and helps
          // find the target user

          // result.VoiceTelephoneNumber != null is also valid

          if (result.DisplayName != null) {
            // to display the user name and telephone number from Active Directory. You can also
            // retrieve more information using similar commands.

            Console.WriteLine(result.DisplayName, result.VoiceTelephoneNumber);
          }
        search.Dispose();
      }

      catch (Exception error) {
        Console.WriteLine("User not found! Error: " + error.Message);
      }
    }
  }
}

using System;
using System.DirectoryServices;
using System.DirectoryServices.AccountManagement;

namespace HybridMethod {
  class getUserInfo {
    static void Main(string[] args) {
      try {
        PrincipalContext userActiveDirectory =
            new PrincipalContext(ContextType.Domain, "Insert your domain link here...");

        // `UserPrincipal` class encapsulates principals that contain user information

        UserPrincipal userName = new UserPrincipal(userActiveDirectory);

        // retrieves the principal context that is essential to perform the query. Its context
        // specifies the server/domain against which search operations are performed.

        PrincipalSearcher searchObj = new PrincipalSearcher(userName);

        foreach (UserPrincipal result in searchObj.FindAll()) {
          if (result.DisplayName != null) {
            // access the underlying object, e.g., user properties

            DirectoryEntry lowerLdap = (DirectoryEntry)result.GetUnderlyingObject();

            Console.WriteLine("{0,30} {1} {2}", result.DisplayName,
                              lowerLdap.Properties["postofficebox"][0].ToString());
          }
        }

        // disposing the `PrincipalSearcher` object

        searchObj.Dispose();
      }

      catch (Exception exp) {
        Console.WriteLine(exp.Message);
      }
    }
  }
}