Facade Pattern in C#

O'Reilly's modern classic Head First Design Patterns describes the Facade pattern as a unified interface to a set of interfaces in a subsystem. Facade defines a higher-level interface that makes the subsystem easier to use.

This pattern is nothing revolutionary and something that all programmers have done at some point, but it is good to have a common name to go by. Today I will demonstrate how to create and remove groups in Active Directory by building a facade.

First, start Visual Studio and create a new project using the class library template. Once created, add a reference to ActiveDs in the project. Next, add a new class named ActiveDirectoryFacade.cs and add Using System.DirectoryServices to that class. Now, add the following function to create a group...

   public static bool CreateGroup(string groupName, out string result)
      {
         bool returnValue = false;
         result = "";

         try
         {
             DirectoryEntry groups = new DirectoryEntry();
             groups.Path = "LDAP://ldap/OU=EmailGroups,DC=yourdomain,DC=com";
             groups.AuthenticationType = AuthenticationTypes.Secure;

             DirectoryEntry group = groups.Children.Add(String.Format("CN={0}", groupName), "group");
             group.Properties["groupType"].Value = ActiveDs.ADS_GROUP_TYPE_ENUM.ADS_GROUP_TYPE_GLOBAL_GROUP;
             group.Properties["mail"].Value = String.Format("{0}@yourdomain.com", groupName);
             group.CommitChanges();

             result = String.Format("Successfully created distribution list {0}", groupName);
             returnValue = true;
         }
         catch (Exception ex)
         {
             result = ex.Message;
             returnValue = false;
         }

         return returnValue;
     }

...and add the following function to remove a group...

     public static bool RemoveGroup(string groupName, out string result)
     {
         bool returnValue = false;
         result = "";

         try
         {
             DirectoryEntry groups = new DirectoryEntry();
             groups.Path = "LDAP://ldap/OU=EmailGroups,DC=yourdomain,DC=com";
             groups.AuthenticationType = AuthenticationTypes.Secure;

             DirectoryEntry group = groups.Children.Find(String.Format("CN={0}", groupName));
             if (group != null)
             {
                 groups.Children.Remove(group);
                 group.CommitChanges();
             }

             result = String.Format("Successfully removed distribution list {0}", groupName);
             returnValue = true;
         }
         catch (Exception ex)
         {
             result = ex.Message;
             returnValue = false;
         }
            
         return returnValue;
     }

We have just created a facade to add and remove Active Directory Groups with two functions. We can now use these functions in our applications.