关键字是 C# 编译器预定义的保留字。这些关键字不能用作标识符，但是，如果您想使用这些关键字作为标识符，可以在关键字前面加上 @ 字符作为前缀。

1. class:

   public class MyClass
   {// Class definition
   }
   

2. interface:

   public interface IMyInterface
   {void MyMethod();
   }
   

3. public:

   public class MyClass
   {public int MyProperty { get; set; }
   }
   

4. private:

   public class MyClass
   {private int myPrivateField;
   }
   

5. protected:

   public class MyBaseClass
   {protected int MyProtectedField;
   }
   

6. internal:

   internal class MyInternalClass
   {// Internal class accessible within the same assembly
   }
   

7. static:

   public static class MyStaticClass
   {public static void MyStaticMethod(){// Static method}
   }
   

8. void:

   public class MyClass
   {public void MyMethod(){// Method that returns void}
   }
   

9. new:

   public class MyBaseClass
   {public virtual void MyMethod(){// Base method}
   }public class MyDerivedClass : MyBaseClass
   {public new void MyMethod(){// Hides base class method with new implementation}
   }
   

10. virtual, override:

    public class MyBaseClass
    {public virtual void MyMethod(){// Virtual method}
    }public class MyDerivedClass : MyBaseClass
    {public override void MyMethod(){// Overrides base class method}
    }
    

11. abstract:

    public abstract class MyAbstractClass
    {public abstract void MyAbstractMethod();
    }
    

12. this:

    public class MyClass
    {private int value;public void SetValue(int value){this.value = value; // 'this' refers to the current instance of MyClass}
    }
    

13. base:

    public class MyBaseClass
    {protected int baseValue;public MyBaseClass(int value){baseValue = value;}
    }public class MyDerivedClass : MyBaseClass
    {public MyDerivedClass(int derivedValue) : base(derivedValue){// Calls base class constructor with 'derivedValue'}
    }
    

14. readonly, const:

    public class MyClass
    {public const int MyConstant = 10;public readonly int MyReadOnlyField;public MyClass(int value){MyReadOnlyField = value; // Readonly field can be initialized in constructor}
    }
    

15. delegate:

    public delegate void MyDelegate(string message);public class MyClass
    {public void MyMethod(string message){Console.WriteLine(message);}
    }// Usage of delegate:
    // MyDelegate handler = new MyDelegate(new MyClass().MyMethod);
    

16. event:

    public class MyClass
    {public event EventHandler MyEvent;public void RaiseEvent(){MyEvent?.Invoke(this, EventArgs.Empty);}
    }
    

17. try, catch, finally:

    try
    {// Code that may throw exceptions
    }
    catch (Exception ex)
    {// Handle exceptions
    }
    finally
    {// Code that always runs, whether an exception occurred or not
    }
    

18. if, else, switch, case:

    int x = 10;if (x > 5)
    {Console.WriteLine("x is greater than 5");
    }
    else
    {Console.WriteLine("x is less than or equal to 5");
    }switch (x)
    {case 5:Console.WriteLine("x is 5");break;default:Console.WriteLine("x is not 5");break;
    }
    

19. for, while, do:

    for (int i = 0; i < 5; i++)
    {Console.WriteLine(i);
    }int j = 0;
    while (j < 5)
    {Console.WriteLine(j);j++;
    }int k = 0;
    do
    {Console.WriteLine(k);k++;
    } while (k < 5);
    

20. foreach:

    int[] numbers = { 1, 2, 3, 4, 5 };foreach (int num in numbers)
    {Console.WriteLine(num);
    }
    

21. lock:

    private object lockObject = new object();public void AccessSharedResource()
    {lock (lockObject){// Code inside this block is thread-safe}
    }
    

22. using:

    using (var resource = new DisposableResource())
    {// Use 'resource' here
    }
    

23. async, await:

    public async Task<int> GetValueAsync()
    {await Task.Delay(1000); // Simulates an async operationreturn 10;
    }// Example of usage:
    // int result = await GetValueAsync();
    

24. get, set:

    public class MyClass
    {private int myProperty;public int MyProperty{get { return myProperty; }set { myProperty = value; }}
    }