C#中的构造函数是什么 C#类的构造函数和析构函数详解

public class Person
{
    public string Name { get; set; }
    
    // 无参构造函数
    public Person()
    {
        Name = "Unknown";
    }

    // 带参构造函数
    public Person(string name)
    {
        Name = name;
    }
}

Person p1 = new Person();           // 调用无参构造函数
Person p2 = new Person("Alice");     // 调用带参构造函数

public class Rectangle
{
    public int Width { get; set; }
    public int Height { get; set; }

    public Rectangle() : this(1, 1) { }                    // 默认尺寸

    public Rectangle(int width) : this(width, width) { }   // 正方形情况

    public Rectangle(int width, int height)
    {
        Width = width;
        Height = height;
    }
}

public class Logger
{
    public static string LogFile;

    static Logger()
    {
        LogFile = "app.log";
        Console.WriteLine("日志系统已初始化");
    }
}

public class FileHandler
{
    private IntPtr filePtr;

    // 析构函数
    ~FileHandler()
    {
        if (filePtr != IntPtr.Zero)
        {
            // 释放非托管资源
            CloseHandle(filePtr);
            filePtr = IntPtr.Zero;
        }
    }

    [System.Runtime.InteropServices.DllImport("kernel32")]
    private static extern bool CloseHandle(IntPtr handle);
}

public class FileManager : IDisposable
{
    private bool disposed = false;

    public void Dispose()
    {
        CleanUp(true);
        GC.SuppressFinalize(this);
    }

    ~FileManager()
    {
        CleanUp(false);
    }

    private void CleanUp(bool disposing)
    {
        if (!disposed)
        {
            if (disposing)
            {
                // 释放托管资源
            }
            // 释放非托管资源
            disposed = true;
        }
    }
}

using (var manager = new FileManager())
{
    // 使用资源
} // 自动调用Dispose()