添加Lesson7

C#进阶/C#进阶.sln

@@ -29,6 +29,10 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Lesson6_泛型约束", "Les
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Lesson6_泛型约束练习", "Lesson6_泛型约束练习\Lesson6_泛型约束练习.csproj", "{3BE8ABBA-44EA-4112-B88B-220C71FBFFC8}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Lesson7_List", "Lesson7_List\Lesson7_List.csproj", "{D63FDE7B-2A03-4A86-9E4F-223AF31F099B}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Lesson7_List练习", "Lesson7_List练习\Lesson7_List练习.csproj", "{1E65491F-EA06-4E4D-9E20-A692C9EB3C79}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -87,6 +91,14 @@ Global
 		{3BE8ABBA-44EA-4112-B88B-220C71FBFFC8}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{3BE8ABBA-44EA-4112-B88B-220C71FBFFC8}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{3BE8ABBA-44EA-4112-B88B-220C71FBFFC8}.Release|Any CPU.Build.0 = Release|Any CPU
+		{D63FDE7B-2A03-4A86-9E4F-223AF31F099B}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{D63FDE7B-2A03-4A86-9E4F-223AF31F099B}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{D63FDE7B-2A03-4A86-9E4F-223AF31F099B}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{D63FDE7B-2A03-4A86-9E4F-223AF31F099B}.Release|Any CPU.Build.0 = Release|Any CPU
+		{1E65491F-EA06-4E4D-9E20-A692C9EB3C79}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{1E65491F-EA06-4E4D-9E20-A692C9EB3C79}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{1E65491F-EA06-4E4D-9E20-A692C9EB3C79}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{1E65491F-EA06-4E4D-9E20-A692C9EB3C79}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

C#进阶/Lesson7_List/Lesson7_List.csproj

@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

C#进阶/Lesson7_List/Program.cs

@@ -0,0 +1,82 @@
+namespace Lesson7_List
+{
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            #region 知识点一 List的本质
+            //List是C#为我们封装好的一个类
+            //它的本质是一个可变类型的泛型数组
+            //List类帮助我们实现了很多方法
+            //比如泛型数组的增删查改
+            #endregion
+
+            #region 知识点二 声明
+            //需要引用命名空间System.Collections.Generic
+            List<int> list = new List<int>();
+            List<string> list2 = new List<string>();
+            #endregion
+
+            #region 知识点三 增删查改
+            //增
+            list.Add(1);
+            list.Add(2);
+            list.Add(3);
+            list2.Add("123");
+            //范围增
+            List<string> list3 = new List<string>();
+            list3.Add("456");
+            list2.AddRange(list3);
+            //插入
+            list.Insert(0,9999);
+
+
+            //删
+            //1.移除指定元素
+            list.Remove(1);
+            //2.移除指定位置的元素
+            list.RemoveAt(0);
+            //3.清空
+            list.Clear();
+
+            //查
+            //1.得到指定位置的元素
+            Console.WriteLine(list[0]);
+            //2.查看元素是否存在
+            if (list.Contains(1))
+            {
+                Console.WriteLine("存在为1的元素");
+            }
+            //3.正向查找元素位置
+            //找到返回位置，找不到返回-1
+            int index = list.IndexOf(1);
+            Console.WriteLine(index);
+            //4.反向查找元素位置
+            //找到返回位置，找不到返回-1
+            index = list.LastIndexOf(1);
+            Console.WriteLine(index);
+
+            //改
+            Console.WriteLine(list[0]);
+            list[0] = 99;
+            Console.WriteLine(list[0]);
+            #endregion
+
+            #region 知识点四 遍历
+            //长度
+            Console.WriteLine(list.Count);
+            //容量
+            //避免产生垃圾
+            Console.WriteLine(list.Capacity);
+            for (int i = 0; i < list.Count; i++)
+            {
+                Console.Write(list[i]);
+            }
+            foreach (Object item in list)
+            {
+                Console.WriteLine(item);
+            }
+            #endregion
+        }
+    }
+}

C#进阶/Lesson7_List练习/Lesson7_List练习.csproj

@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

C#进阶/Lesson7_List练习/Program.cs

@@ -0,0 +1,62 @@
+namespace Lesson7_List练习
+{
+    #region 第二题
+    abstract class Monster
+    {
+        public static List<Monster> monsters = new List<Monster>();
+        public Monster()
+        {
+            monsters.Add(this);
+        }
+
+        public abstract void Atk();
+    }
+    class Boss: Monster
+    {
+
+        public override void Atk()
+        {
+            Console.WriteLine("Boss攻击");
+        }
+    }
+    class Goblin : Monster
+    {
+
+        public override void Atk()
+        {
+            Console.WriteLine("哥布林攻击");
+        }
+    }
+    #endregion
+    class Program
+    {
+        static void Main(string[] args)
+        {
+            #region 第一题
+            List<int> l1 = new List<int>();
+            for (int i = 10; i > 0; i--)
+            {
+                l1.Add(i);
+            }
+            l1.RemoveAt(4);
+            for (int i = 0; i < l1.Count; i++)
+            {
+                Console.WriteLine(l1[i]);
+            }
+            Console.WriteLine("_______________________________");
+            #endregion
+
+            #region 第二题
+            Monster m1 = new Boss();
+            Monster m2 = new Goblin();
+
+            Boss b = new Boss();
+            Goblin g = new Goblin();
+            for (int i = 0;i < Monster.monsters.Count;i++)
+            {
+                Monster.monsters[i].Atk();
+            }
+            #endregion
+        }
+    }
+}