事件处理器 `async void FunName()` `async ()=> {} `

事件处理器 async void FunName() async ()=> {}

class Program
{
    static async Task Main()
    {
        var button = new Button();
        button.Click += Button_Click;
        button.SimulateClick();
        System.Console.WriteLine("do other things in Main method...");
        await Task.Delay(1000); // 等待事件处理完成
        System.Console.WriteLine("Main method completed.");
    }

    // 👇👇👇👇👇👇👇👇👇👇👇👇👇👇👇👇👇👇👇👇👇👇
    // 事件处理器必须是 void 返回类型
    static async void Button_Click(object? sender, EventArgs e)
    {
        await Task.Delay(500);
        Console.WriteLine("Button clicked!");
    }
}

public class Button
{
    public event EventHandler? Click;

    public void SimulateClick()
    {
        Click?.Invoke(this, EventArgs.Empty);
    }
}

class Program
{
    static async Task Main()
    {
        var button = new Button();


        // 👇👇👇👇👇👇👇👇👇👇👇👇👇👇👇
        button.Click += async (sender, args) =>
        {
            await Task.Delay(500);
            Console.WriteLine("Button clicked!");
        };

        button.SimulateClick();
        System.Console.WriteLine("do other things in Main method...");
        await Task.Delay(1000); // 等待事件处理完成
        System.Console.WriteLine("Main method completed.");
    }
}

public class Button
{
    public event EventHandler? Click;

    public void SimulateClick()
    {
        Click?.Invoke(this, EventArgs.Empty);
    }
}