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C#: implicit

使用手冊C# · 實用指南

聲明編譯器無需明確強制轉換即可套用的自訂轉換。

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
Count count = 7;
System.Console.WriteLine(count.Value);
readonly record struct Count(int Value)
{
    public static implicit operator Count(int value) => new(value);
}

結果:

7

句法

public static implicit operator Target(Source 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)
    {
        Distance distance = 12;
        Console.WriteLine((int)distance);
    }
}
public readonly record struct Distance(int Value) { public static implicit operator Distance(int value) => new(value); public static explicit operator int(Distance value) => value.Value; }

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)
    {
        Label label = "ore";
        Console.WriteLine((string)label);
    }
}
public readonly record struct Label(string Text) { public static implicit operator Label(string text) => new(text); public static explicit operator string(Label label) => label.Text; }

官方來源：Microsoft學習。