修改Lesson13名称

添加Lesson13练习

C#核心/C#核心.sln

@@ -11,12 +11,14 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Lesson10_封装-运算符
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Lesson11_封装-内部类与外部类", "Lesson11_封装-内部类与外部类\Lesson11_封装-内部类与外部类.csproj", "{97B96262-E4CC-4A7B-8545-D58984CCBD70}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Lesson13_继承-李氏替换原则", "Lesson13_继承-李氏替换原则\Lesson13_继承-李氏替换原则.csproj", "{06C184C2-C60B-4CFC-B3B8-7A8E0754D725}"
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Lesson13_继承-里氏替换原则", "Lesson13_继承-李氏替换原则\Lesson13_继承-里氏替换原则.csproj", "{06C184C2-C60B-4CFC-B3B8-7A8E0754D725}"
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Lesson12_继承-继承的基本概念练习", "Lesson12_继承-继承的基本概念练习\Lesson12_继承-继承的基本概念练习.csproj", "{B432065F-FFA2-4866-BC75-8AC33869B92F}"
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Lesson12_继承-继承的基本概念", "Lesson12_继承-继承的基本概念\Lesson12_继承-继承的基本概念.csproj", "{45F37FBC-59A8-4FC9-B0F5-5CEA222D8C7E}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Lesson13_继承-里氏替换原则练习", "Lesson13_继承-里氏替换原则练习\Lesson13_继承-里氏替换原则练习.csproj", "{B17DEE02-D1AD-460B-8295-DDDE32A0EDA7}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -51,6 +53,10 @@ Global
 		{45F37FBC-59A8-4FC9-B0F5-5CEA222D8C7E}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{45F37FBC-59A8-4FC9-B0F5-5CEA222D8C7E}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{45F37FBC-59A8-4FC9-B0F5-5CEA222D8C7E}.Release|Any CPU.Build.0 = Release|Any CPU
+		{B17DEE02-D1AD-460B-8295-DDDE32A0EDA7}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{B17DEE02-D1AD-460B-8295-DDDE32A0EDA7}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{B17DEE02-D1AD-460B-8295-DDDE32A0EDA7}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{B17DEE02-D1AD-460B-8295-DDDE32A0EDA7}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

C#核心/Lesson13_继承-李氏替换原则/Program.cs

@@ -1,10 +1,115 @@
 namespace Lesson13_继承_李氏替换原则
 {
+
+    #region 知识点一 基本概念
+    //里氏替换原则是面向对象七大原则中最重要的原则
+    //概念：
+    //任何父类出现的地方，子类都可以替代
+    //重点：
+    //语法表现——父类容器装子类对象，因为子类对象包含了父类的所有内容
+    //作用：
+    //方便进行对象存储和管理
+    #endregion
+
+    #region 知识点二 基本实现
+    class GameObject
+    {
+
+    }
+    class Player:GameObject
+    {
+        public void PlayerAtk()
+        {
+            Console.WriteLine("玩家攻击");
+        }
+    }
+    class Monster :GameObject
+    {
+        public void MonsterAtk()
+        {
+            Console.WriteLine("怪物攻击");
+        }
+    }
+    class Boss:GameObject
+    {
+        public void BossAtk()
+        {
+            Console.WriteLine("Boss攻击");
+        }
+    }
+    #endregion
+
+
     internal class Program
     {
         static void Main(string[] args)
         {
             Console.WriteLine("Hello, World!");
+            //里氏替换原则
+            GameObject player = new Player();
+            GameObject monster = new Monster();
+            GameObject boss = new Boss();
+
+            GameObject[] objects = new GameObject[] { player, monster, boss };
+
+            //player.atk();//容器是gameobject,没有atk这个方法
+
+            #region 知识点三 is和as
+            //基本概念
+            //is：判断一个对象是否执行类对象
+            //返回时：bool 是为真 不是为假
+            if (player is Player)
+            {
+                
+            }else if (player is Monster)
+            {
+
+            }
+
+            //as：将一个对象转换为指定类对象
+            //返回值：指定类型对象
+            //成功返回指定类型对象，失败返回null
+            Player test = player as Player;//将player转换为Player类型对象（可）返回player类型对象(Player 类型的 test，存放player)
+            Player test2 = monster as Player;//将monster转换为Player类型对象（报错）返回空(Player 类型的 test2, 存放的是空)
+
+            
+            //基本语法
+            // 类对象 is 类名  该语句块 会有一个bool返回值 true和false
+            // 类对象 as 类名  该语句块 会有一个对象返回值 对象和null
+            // 一般组合使用
+            if(player is Player)
+            {
+                //常规写法
+                //Player p1 = player as Player;
+                //p1.PlayerAtk();
+
+                //一句话写法
+                (player as Player).PlayerAtk();
+            }
+            //同时声明多个子类对象，并集中按需使用  ->GameObject[] objects = new GameObject[] { player, monster, boss };
+            for (int i = 0; i < objects.Length; i++)
+            {
+                if (objects[i] is Player)
+                {
+                    //调用Player需要的逻辑
+                    //eg:
+                    (objects[i] as Player).PlayerAtk();
+                }
+                else if (objects[i] is Monster)
+                {
+                    //调用Monster需要的逻辑
+                    //eg:
+                    (objects[i] as Monster).MonsterAtk();
+                }
+                else if (objects[i] is Boss)
+                {
+                    //调用Boss需要的逻辑
+                    //eg:
+                    (objects[i] as Boss).BossAtk();
+                }
+            }
+
+            #endregion
         }
     }
 }

C#核心/Lesson13_继承-里氏替换原则练习/Lesson13_继承-里氏替换原则练习.csproj

@@ -0,0 +1,11 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <RootNamespace>Lesson13_继承_里氏替换原则练习</RootNamespace>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

C#核心/Lesson13_继承-里氏替换原则练习/Program.cs

@@ -0,0 +1,134 @@
+namespace Lesson13_继承_里氏替换原则练习
+{
+    class Monster
+    {
+
+    }
+    class Boss : Monster
+    {
+        public void Skill()
+        {
+            Console.WriteLine("Boss释放了技能");
+        }
+    }
+    class Goblin : Monster
+    {
+        public void Atk()
+        {
+            Console.WriteLine("小怪释放了攻击");
+        }
+    }
+    class Weapon
+    {
+        
+    }
+    class SMG : Weapon
+    {
+        public void Shot()
+        {
+            Console.WriteLine("SMG shot");
+        }
+    }
+    class Shotgun : Weapon
+    {
+        public void Shot()
+        {
+            Console.WriteLine("Shotgun shot");
+        }
+    }
+    class Pistol : Weapon
+    {
+        public void Shot()
+        {
+            Console.WriteLine("Pistol shot");
+        }
+    }
+    class Knife : Weapon
+    {
+        public void Attack()
+        {
+            Console.WriteLine("Knife Attack");
+        }
+    }
+    class Player
+    {
+        private Weapon nowWeapon;
+
+        public Player()
+        {
+            nowWeapon = new Knife();
+        }
+        public void PickUp(Weapon newWeapon)
+        {
+            nowWeapon = newWeapon;
+        }
+        public void Attack()
+        {
+            if (nowWeapon == null)
+            {
+                Console.WriteLine("你没有武器");
+            }else if (nowWeapon is Knife)
+            {
+                (nowWeapon as Knife).Attack();
+            }else if(nowWeapon  is Pistol)
+            {
+                (nowWeapon as Pistol).Shot();
+            }
+            else if (nowWeapon is Shotgun)
+            {
+                (nowWeapon as Shotgun).Shot();
+            }
+            else if (nowWeapon is SMG)
+            {
+                (nowWeapon as SMG).Shot();
+            }
+            else
+            {
+                Console.WriteLine("ERROR");
+            }
+        }
+    }
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            Console.WriteLine("Hello, World!");
+            Random r = new Random();
+            
+            Monster[] m = new Monster[10];
+            for (int i = 0; i < m.Length; i++)
+            {
+                if (r.Next(1, 101) < 50)
+                {
+                    m[i] = new Boss();
+                }
+                else
+                {
+                    m[i] = new Goblin();
+                }
+            }
+            for (int i = 0;i < m.Length;i++)
+            {
+                if (m[i] is Boss)
+                {
+                    (m[i] as Boss).Skill();
+                }else if (m[i] is Goblin)
+                {
+                    (m[i] as Goblin).Atk();
+                }
+                else
+                {
+                    Console.WriteLine("Error");
+                }
+            }
+
+
+            Console.WriteLine();
+            Player p1 = new Player();
+            p1.Attack();
+            SMG smg1 = new SMG();
+            p1.PickUp(smg1);
+            p1.Attack();
+        }
+    }
+}

C#核心/test/Program.cs

@@ -1,2 +1,25 @@
 // See https://aka.ms/new-console-template for more information
 Console.WriteLine("Hello, World!");
+#region 知识点一 
+#endregion
+
+#region 知识点二 
+#endregion
+
+#region 知识点三 
+#endregion
+
+#region 知识点四 
+#endregion
+
+#region 知识点五 
+#endregion
+
+#region 知识点六 
+#endregion
+
+#region 知识点七 
+#endregion
+
+#region 知识点八 
+#endregion