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C#: with

使用手冊C# · 實用指南

建立記錄、結構或匿名物件的修改副本。嵌入的連結是表面複製的。

簡單範例 (Example.cs)

請將此範例另存為 Example.cs，並與本頁其他範例分開執行。

Example.cs:

// PROJECT-EXAMPLE
var original = new Item("ore", 1);
var copy = original with { Count = 3 };
System.Console.WriteLine($"{original.Count}:{copy.Count}");
record Item(string Name, int Count);

結果:

1:3

句法

var changed = original with { Member = value };

例1：基本形式

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using System.IO;
using System.Runtime.InteropServices;
using System.Runtime.CompilerServices;

public static class Program
{
    public static async Task Main(string[] args)
    {
        Person first = new("Archer", 2);
        Person next = first with { Level = 3 };
        Console.WriteLine($"{first.Level}:{next.Level}");
    }
}
public record Person(string Name, int Level);

例2：另一種實用形式

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using System.IO;
using System.Runtime.InteropServices;
using System.Runtime.CompilerServices;

public static class Program
{
    public static async Task Main(string[] args)
    {
        var first = new { Name = "Ore", Count = 5 };
        var next = first with { Count = 8 };
        Console.WriteLine($"{first.Count}:{next.Count}");
    }
}

官方來源：Microsoft學習。