visitor pattern

DesignPattern/DesignPattern/Patterns/VisitorPattern.cs

@@ -0,0 +1,101 @@
+namespace DesignPattern.Patterns
+{
+    internal class VisitorPattern
+    {
+        public interface ICarElement
+        {
+            void Accept(ICarVisitor visitor);
+        }
+
+        public class Engine : ICarElement
+        {
+            public string Spec => "V4";
+            void ICarElement.Accept(ICarVisitor visitor)
+            {
+                visitor.Visit(this);
+            }
+        }
+
+        public class Body : ICarElement
+        {
+            public string Color => "Silver";
+            void ICarElement.Accept(ICarVisitor visitor)
+            {
+                visitor.Visit(this);
+            }
+        }
+
+        public class Wheel : ICarElement
+        {
+            public string Type => "P26";
+            void ICarElement.Accept(ICarVisitor visitor)
+            {
+                visitor.Visit(this);
+            }
+        }
+
+        public class Car : ICarElement
+        {
+            public string Maker => "BMW";
+            private List<ICarElement> _elements;
+
+            public Car()
+            {
+                _elements = new List<ICarElement>()
+                {
+                    new Engine(),
+                    new Body(),
+                    new Wheel(),
+                };
+            }
+
+            void ICarElement.Accept(ICarVisitor visitor)
+            {
+                foreach (var elem in _elements)
+                {
+                    elem.Accept(visitor);
+                }
+
+                visitor.Visit(this);
+            }
+        }
+
+        public interface ICarVisitor
+        {
+            void Visit(Engine elememt);
+            void Visit(Body elememt);
+            void Visit(Wheel elememt);
+            void Visit(Car elememt);
+        }
+
+        public class CarPrintVisitor : ICarVisitor
+        {
+            void ICarVisitor.Visit(Engine elememt)
+            {
+                Console.WriteLine(elememt.Spec);
+            }
+
+            void ICarVisitor.Visit(Body elememt)
+            {
+                Console.WriteLine(elememt.Color);
+            }
+
+            void ICarVisitor.Visit(Wheel elememt)
+            {
+                Console.WriteLine(elememt.Type);
+            }
+
+            void ICarVisitor.Visit(Car elememt)
+            {
+                Console.WriteLine(elememt.Maker);
+            }
+        }
+
+        public static void Work()
+        {
+            ICarElement car = new Car();
+            ICarVisitor visitor = new CarPrintVisitor();
+            car.Accept(visitor);
+        }
+    }
+}

DesignPattern/DesignPattern/Program.cs

@@ -10,6 +10,8 @@ class Program
 
         // CommandClient.Work();
 
-        StateMachinePattern.Work();
+        //StateMachinePattern.Work();
+
+        VisitorPattern.Work();
     }
 }