The Elegant Art of Programming

This is an alternative to the original poster's "solution 1", which really does need some help.

    public static bool
    AllTheSame<T>
    (                                 
      this System.Collections.Generic.IList<T> List
    )                                      
    where T : System.IEquatable<T>
    {                                                  
      if ( List == null )
      {
        throw ( new System.ArgumentNullException ( "List" , "List must not be null" ) ) ;
      }

      bool result = true ;

      if ( List.Count > 1 )
      {                                
        T first = List [ 0 ] ;    
                                
        if ( (object) first == null )
        {
          for ( int i = 1 ; result && ( i < List.Count ) ; i++ )
          {
            result = (object) List [ i ] == null ;
          }
        }
        else
        {
          for ( int i = 1 ; result && ( i < List.Count ) ; i++ )
          {                         
            result = first.Equals ( List [ i ] ) ;
          }
        }
      }
    
      return ( result ) ;
    }