title: Is this a true implementation of Singleton Pattern?
body: <p>All tutorials I've read till now about Singleton pattern were as below :</p>
  
  <pre><code> public sealed class Singleton
   {
        private static readonly Singleton instance = new Singleton();
  
        private Singleton(){}
  
        public static Singleton Instance
        {
           get 
           {
              return instance; 
           }
        }
   }
  </code></pre>
  
  <p>but I already have a class in a assembly that I need to just have one instance of it during application lifetime . I don't know how to use pattern mentioned above .</p>
  
  <p>for example suppose there is a class X in dll named Y . is the code below correct :</p>
  
  <pre><code> public sealed class Singleton
   {
        private static readonly Y.X instance = new Y.X();
  
        private Singleton(){}
  
        public static Y.X Instance
        {
           get 
           {
              return instance; 
           }
        }
   }
  </code></pre>
  
  <p>is this a true singleton ? if not , what is a correct way to handle this situation ?</p>