There is a requirement to perform CRUD operation on an Active Directory and we need to create it on C#. The following code will help an engineer accordingly:

Create

using (DirectoryEntry directoryEntry = new DirectoryEntry("LDAP:\\url\ou", "username", "password"))
                {
                    using (DirectoryEntry newUser = directoryEntry.Children.Add("CN=Name", "User"))
                    {
                        if (!DirectoryEntry.Exists(newUser.Path))
                        {
                            newUser.Properties["property1"].Add(propertyValue);
                            newUser.CommitChanges();
                            ret = true;
                        }
                    }
                }

Update

using (DirectoryEntry directoryEntry = new DirectoryEntry("LDAP:\\url\ou", "username", "password"))
                {
                    using (DirectorySearcher search = new DirectorySearcher(directoryEntry))
                    {
                        search.Filter = String.Format("(IdentifierProperty={0})", identifier);
                        search.PropertiesToLoad.Add("property1");
                        SearchResult result = search.FindOne();
                        if (result != null)
                        {
                            using (DirectoryEntry entryToUpdate = result.GetDirectoryEntry())
                            {
                                entryToUpdate.Properties["property1"].Value = "property1value";
                                entryToUpdate.CommitChanges();
                                ret = true;
                            }
                        }
                    }
                }

Delete

using (DirectoryEntry directoryEntry = new DirectoryEntry("LDAP:\\url\ou", "username", "password"))
                {
                    using (DirectorySearcher search = new DirectorySearcher(directoryEntry))
                    {
                        search.Filter = String.Format("(IdentifierProperty={0})", identifier);
                        search.PropertiesToLoad.Add("property1");
                        SearchResult result = search.FindOne();
                        if (result != null)
                        {
                            using (DirectoryEntry entryToUpdate = result.GetDirectoryEntry())
                            {
                                directoryEntry.Children.Remove(entryToUpdate);
                                directoryEntry.CommitChanges();
                                ret = true;
                            }
                        }
                    }
                }