增加C#5。0

data/1..NET初阶/3.C#特性/2.C#4.0特性/Dynamic.json

+{
+  "type": "code_options",
+  "author": "huanhuilong",
+  "source": "Covariance.md",
+  "notebook_enable": false,
+  "exercise_id": "5e0d3fafff5f414681d29c840d3d24f5"
+}
\ No newline at end of file

data/1..NET初阶/3.C#特性/2.C#4.0特性/Dynamic.md

+# dynamic 类型
+
+下面的代码在编译时时错误的：
+
+```csharp
+// 编译错误，object和int不能相加
+object n = 10;
+int result = n + 5;
+Console.WriteLine("result:{0}", result);
+```
+
+而下面的代码可以在编译时通过，运行时正常执行：
+
+```csharp
+// 编译时不检查类型，运行时才检查
+dynamic n = 10;
+int result = n + 5;
+Console.WriteLine("result:{0}", result);
+```
+
+dynamic 的用途就是在编译时忽略类型检查，延迟到运行期再检查。现在有下面的代码
+
+```csharp
+class Test{
+    public static dynamic Double(dynamic d){
+        if (d is int){
+            return d*2;
+        }else if(d is string){
+            return d+d;
+        }else{
+            throw new Exception("Not support");
+        }
+    }
+}
+```
+
+以下关于 上述 dynamic 的代码调用，运行时会出错的是？
+
+## 答案
+
+```csharp
+Console.WriteLine(Test.Double(new object()));
+```
+
+## 选项
+
+
+### A
+```csharp
+Console.WriteLine(Test.Double(10));
+```
+
+### B
+```csharp
+Console.WriteLine(Test.Double("10"));
+```
+
+### C
+```csharp
+Console.WriteLine(Test.Double(10/2));
+```
\ No newline at end of file

data/1..NET初阶/3.C#特性/2.C#4.0特性/config.json

 {
   "node_id": "csharp-d4650354f5f5498e9969fd98bbb40323",
   "keywords": [
-    "协变和逆变",
+    "dynamic",
     "命名参数",
     "可选参数",
-    "动态查找"
+    "协变和逆变"
   ],
   "children": [],
   "export": [
+    "Dynamic.json",
     "OptionParam.json",
     "NamedParam.json",
     "Covariance.json",

data/1..NET初阶/3.C#特性/2.C#4.0特性/sample/Program.cs

 // See https://aka.ms/new-console-template for more information
 Console.WriteLine("Hello, World!");
 
+
+
+Console.WriteLine(Test.Double(10/2));
+// Console.WriteLine(Test.Double("10"));
+// Console.WriteLine(Test.Double(new object()));
+
+class Test{
+    public static dynamic Double(dynamic d){
+        if (d is int){
+            return d*2;
+        }else if(d is string){
+            return d+d;
+        }else{
+            throw new Exception("Not support");
+        }
+    }
+}
+
+
+
+// 编译错误
+// object n = 10;
+// int result = n + 5;
+// Console.WriteLine("result:{0}", result);
+
+// 编译时不检查，运行时才检查
+// dynamic n = "10";
+// int result = n + 5;
+// Console.WriteLine("result:{0}", result);
+
 // // // 协变代码
 // ISearch<Article> search = new CodeArticleSearch<CodeArticle>();
 // Article article = search.Search();
@@ -18,50 +48,50 @@ Console.WriteLine("Hello, World!");
 
 
 // Test.Find(key:"hello", number:5);
-Test.Find(key:"hello", sort:false, number:5);
-Test.Find(sort:false, number:5, key:"hello");
-
-
-static class Test{
-    public static List<string> Find(string key, int number, bool sort){
-        Console.WriteLine("key:{0}, number:{1}, sort:{2}", key, number, sort);
-        return new List<string>(){};
-    }
-}
-
-
-// 父类和子类
-class Article{
-    public string ToString(){
-        return "article";
-    }
-}
-
-class CodeArticle: Article{
-    public string ToString(){
-        return "article with code";
-    }
-}
-
-
-// 协变
-public interface ISearch<out T> {    
-    T Search();
-}
-
-public class CodeArticleSearch<T>: ISearch<T> where T:new(){
-    public T Search(){
-        return new T();
-    }
-}
-
-// 逆变
-public interface ISend<in T> {    
-    void Send(T t);
-}
-
-public class ArticleSender<T> : ISend<T>{
-    public void Send(T t){
-        Console.WriteLine("Send:{0}", t.ToString());
-    }
-}
\ No newline at end of file
+// Test.Find(key:"hello", sort:false, number:5);
+// Test.Find(sort:false, number:5, key:"hello");
+
+
+// static class Test{
+//     public static List<string> Find(string key, int number, bool sort){
+//         Console.WriteLine("key:{0}, number:{1}, sort:{2}", key, number, sort);
+//         return new List<string>(){};
+//     }
+// }
+
+
+// // 父类和子类
+// class Article{
+//     public string ToString(){
+//         return "article";
+//     }
+// }
+
+// class CodeArticle: Article{
+//     public string ToString(){
+//         return "article with code";
+//     }
+// }
+
+
+// // 协变
+// public interface ISearch<out T> {    
+//     T Search();
+// }
+
+// public class CodeArticleSearch<T>: ISearch<T> where T:new(){
+//     public T Search(){
+//         return new T();
+//     }
+// }
+
+// // 逆变
+// public interface ISend<in T> {    
+//     void Send(T t);
+// }
+
+// public class ArticleSender<T> : ISend<T>{
+//     public void Send(T t){
+//         Console.WriteLine("Send:{0}", t.ToString());
+//     }
+// }
\ No newline at end of file

data/1..NET初阶/3.C#特性/3.C#5.0特性/AsyncAwait.json

+{
+  "type": "code_options",
+  "author": "huanhuilong",
+  "source": "AsyncAwait.md",
+  "notebook_enable": false,
+  "exercise_id": "857ced4d29204906b695e8b97ff914ee"
+}
\ No newline at end of file

data/1..NET初阶/3.C#特性/3.C#5.0特性/AsyncAwait.md

+# 异步任务(async, await, Task)
+
+下面的代码是同步执行的：
+```csharp
+// 同步
+Console.WriteLine("调用 DoSomethingSync 之前");
+DoSomethingSync();
+Console.WriteLine("调用 DoSomethingSync 之后");
+
+void DoSomethingSync(){
+    Thread.Sleep(1000);
+    Console.WriteLine("等我一秒钟");
+}
+```
+
+输出的结果是：
+
+```csharp
+调用 DoSomethingSync 之前
+等我一秒钟
+调用 DoSomethingSync 之后
+```
+
+而下面的代码是异步执行的：
+
+```csharp
+// 异步
+Console.WriteLine("调用 DoSomethingAsync 之前");
+Task task = DoSomethingAsync();
+Console.WriteLine("调用 DoSomethingAsync 之后");
+
+await task;
+
+async Task DoSomethingAsync(){
+    await Task.Delay(10000);
+    Console.WriteLine("等我一秒钟");
+}
+```
+
+输出结果是：
+
+```csharp
+调用 DoSomethingAsync 之前
+调用 DoSomethingAsync 之后
+等我一秒钟
+```
+
+几个关键的地方是
+* async 方法必须返回一个Task
+* 一个 Task 可以被异步执行，程序继续往下执行主线逻辑
+* 一个 Task，可以被 await（异步等待）
+* 通过 await 一个Task，则必须等待异步任务完成后才继续往下执行
+
+下面关于 async, await 说法错误的是？
+
+## 答案
+
+```csharp
+// 以下代码的输出是
+// ==
+// "调用 DoSomethingAsync 之前"
+// "调用 DoSomethingAsync 之后"
+// "等我一秒钟"
+//
+Console.WriteLine("调用 DoSomethingAsync 之前");
+Task task = DoSomethingAsync();
+Console.WriteLine("调用 DoSomethingAsync 之后");
+
+await task;
+
+async Task DoSomethingAsync(){
+    await Thread.Sleep(1000);
+    Console.WriteLine("等我一秒钟");
+}
+```
+
+## 选项
+
+### A
+
+```csharp
+// 以下代码的输出是
+// ==
+// "调用 DoSomethingAsync 之前"
+// "等我一秒钟"
+// "调用 DoSomethingAsync 之后"
+//
+Console.WriteLine("调用 DoSomethingAsync 之前");
+Task task = DoSomethingAsync();
+Console.WriteLine("调用 DoSomethingAsync 之后");
+
+await task;
+
+async Task DoSomethingAsync(){
+    Task.Delay(10000);
+    Console.WriteLine("等我一秒钟");
+}
+```
+
+### B
+
+```csharp
+// 以下代码的输出是
+// ==
+// "调用 DoSomethingAsync 之前"
+// "调用 DoSomethingAsync 之后"
+//
+Console.WriteLine("调用 DoSomethingAsync 之前");
+Task task = DoSomethingAsync();
+Console.WriteLine("调用 DoSomethingAsync 之后");
+
+async Task DoSomethingAsync(){
+    Thread.Sleep(1000);
+    Console.WriteLine("等我一秒钟");
+}
+```
+
+### C
+
+```csharp
+// 以下代码的输出是
+// ==
+// "调用 DoSomethingAsync 之前"
+// "调用 DoSomethingAsync 之后"
+// "等我一秒钟"
+//
+Console.WriteLine("调用 DoSomethingAsync 之前");
+Task task = DoSomethingAsync();
+Console.WriteLine("调用 DoSomethingAsync 之后");
+await task;
+
+async Task DoSomethingAsync(){
+    Task delay = Task.Delay(1000);
+    await delay;
+    Console.WriteLine("等我一秒钟");
+}
+```
\ No newline at end of file

data/1..NET初阶/3.C#特性/3.C#5.0特性/CallerInfo.json

+{
+  "type": "code_options",
+  "author": "huanhuilong",
+  "source": "CallerInfo.md",
+  "notebook_enable": false,
+  "exercise_id": "1248fc45c96849e383437b49ac38d405"
+}
\ No newline at end of file

data/1..NET初阶/3.C#特性/3.C#5.0特性/CallerInfo.md

+# 函数调用者信息
+
+通常我们会封装一个函数用来打印日志，但是在在日志函数里，会丢失掉这个日志函数在哪个地方被调用的信息，缺失这个信息会导致诊断问题的时候不方便直接找到出问题的位置。
+
+下面的代码，会在编译期把函数调用位置的信息记录下来，在运行时打印出来。
+
+```csharp
+using  System.Runtime.CompilerServices;
+
+TraceMessage("HelloWorld");
+
+void TraceMessage(string message,
+        [CallerMemberName] string memberName = "",
+        [CallerFilePath] string sourceFilePath = "",
+        [CallerLineNumber] int sourceLineNumber = 0)
+{
+    Console.WriteLine("message: " + message);
+    Console.WriteLine("member name: " + memberName);
+    Console.WriteLine("source file path: " + sourceFilePath);
+    Console.WriteLine("source line number: " + sourceLineNumber);
+}
+```
+
+输出信息是：
+```bash
+message: HelloWorld
+member name: <Main>$
+source file path: ...../Program.cs
+source line number: 3
+```
+
+以下说法错误的是？
+
+## 答案
+
+```csharp
+使用调用者信息属性，不需要引入 using  System.Runtime.CompilerServices;
+```
+
+
+## 选项
+
+### A
+
+```csharp
+[CallerMemberName] 是函数参数的属性标记，这是CSharp特有的语法
+```
+
+### B
+
+```csharp
+//
+// （1）和（2）输出的 source line number 不同
+// 
+
+using  System.Runtime.CompilerServices;
+
+Test();
+
+void Test(){
+    TraceMessage("HelloWorld"); //（1）
+    TraceMessage("HelloWorld"); //（2）
+}
+
+void TraceMessage(string message,
+        [CallerMemberName] string memberName = "",
+        [CallerFilePath] string sourceFilePath = "",
+        [CallerLineNumber] int sourceLineNumber = 0)
+{
+    Console.WriteLine("message: " + message);
+    Console.WriteLine("member name: " + memberName);
+    Console.WriteLine("source file path: " + sourceFilePath);
+    Console.WriteLine("source line number: " + sourceLineNumber);
+}
+```
+
+### C
+
+```csharp
+//
+// （1）和（2）输出的 source file path 和 member name 相同
+// 
+
+using  System.Runtime.CompilerServices;
+
+Test();
+
+void Test(){
+    TraceMessage("HelloWorld"); //（1）
+    TraceMessage("HelloWorld"); //（2）
+}
+
+void TraceMessage(string message,
+        [CallerMemberName] string memberName = "",
+        [CallerFilePath] string sourceFilePath = "",
+        [CallerLineNumber] int sourceLineNumber = 0)
+{
+    Console.WriteLine("message: " + message);
+    Console.WriteLine("member name: " + memberName);
+    Console.WriteLine("source file path: " + sourceFilePath);
+    Console.WriteLine("source line number: " + sourceLineNumber);
+}
+```
\ No newline at end of file

data/1..NET初阶/3.C#特性/3.C#5.0特性/config.json

 {
   "node_id": "csharp-730d385761c64702b710308c91271c9c",
   "keywords": [
-    "case支持表达式",
-    "带参数的泛型构造函数",
-    "扩展属性",
-    "支持null类型运算",
-    "绑定运算符，:=:"
+    "async",
+    "await",
+    "caller information"
   ],
   "children": [],
-  "export": [],
+  "export": [
+    "AsyncAwait.json",
+    "CallerInfo.json"
+  ],
   "keywords_must": [],
   "keywords_forbid": []
 }
\ No newline at end of file

data/1..NET初阶/3.C#特性/3.C#5.0特性/sample/Program.cs

+using  System.Runtime.CompilerServices;
+
+Test();
+
+void Test(){
+    TraceMessage("HelloWorld"); //（1）
+    TraceMessage("HelloWorld"); //（2）
+}
+
+void TraceMessage(string message,
+        [CallerMemberName] string memberName = "",
+        [CallerFilePath] string sourceFilePath = "",
+        [CallerLineNumber] int sourceLineNumber = 0)
+{
+    Console.WriteLine("message: " + message);
+    Console.WriteLine("member name: " + memberName);
+    Console.WriteLine("source file path: " + sourceFilePath);
+    Console.WriteLine("source line number: " + sourceLineNumber);
+}
+
+// 同步
+// Console.WriteLine("调用 DoSomethingSync 之前");
+// DoSomethingSync();
+// Console.WriteLine("调用 DoSomethingSync 之后");
+
+// void DoSomethingSync(){
+//     Thread.Sleep(1000);
+//     Console.WriteLine("等我一秒钟");
+// }
+
+// 异步
+
+// Console.WriteLine("调用 DoSomethingAsync 之前");
+// Task task = DoSomethingAsync();
+// Console.WriteLine("调用 DoSomethingAsync 之后");
+// await task;
+
+// async Task DoSomethingAsync(){
+//     Task delay = Task.Delay(1000);
+//     await delay;
+//     Console.WriteLine("等我一秒钟");
+// }
+
+
+
+
+
+
+
+
+

data/1..NET初阶/3.C#特性/3.C#5.0特性/sample/sample.csproj

+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

data/tree.json

@@ -210,10 +210,10 @@
                     "C#4.0特性": {
                       "node_id": "csharp-d4650354f5f5498e9969fd98bbb40323",
                       "keywords": [
-                        "协变和逆变",
+                        "dynamic",
                         "命名参数",
                         "可选参数",
-                        "动态查找"
+                        "协变和逆变"
                       ],
                       "children": [],
                       "keywords_must": [],