C# Blazor WebAssembly：参数 2：无法从"void"转换为"Microsoft.AspNetCore.Components.EventCallback"

Question

我是blazor C#的新手，正在尝试制作一个简单的倒计时计时器网站。我的网站包括：

• 显示计时器的文本
• 启动和停止按钮
• 设置计时器的按钮

我设置计时器的按钮有问题。当我点击它时，它不会设置计时器显示，我得到了一个错误Argument 2: cannot convert from 'void' to 'Microsoft.AspNetCore.Components.EventCallback'。我在Youtube上搜索EventCallback主题，但问题是，我的组件没有分离，而在视频中，示例代码将分离的组件链接在一起。这是代码
指数剃刀

@page "/"
@inherits FrontEnd.Components.Timer
<h1>Timer</h1>
<p class="timer">@Hours.ToString("00"):@Minutes.ToString("00"):@Seconds.ToString("00")</p>
@foreach (var timer in timerCollections)
{
// Here's the problem
<button @onclick="SetTimer(timer.Id)">@timer.Hours.ToString("00"):@timer.Minutes.ToString("00"):@timer.Seconds.ToString("00")</button>
}
<br/>
<button @onclick="StartTimer" disabled=@StartButtonIsDisabled>Start</button>
<button @onclick="StopTimer" disabled=@StopButtonIsDisabled>Stop</button>

定时器.cs

using System;
using System.Timers;
using System.Collections.Generic;
using Microsoft.AspNetCore.Components;
namespace FrontEnd.Components
{
public class TimerStructure
{
public int Id { get; set; }
public int Hours { get; set; }
public int Minutes { get; set; }
public int Seconds { get; set; }      
}
public class Timer : ComponentBase
{
public List<TimerStructure> timerCollections = new List<TimerStructure>(){
new TimerStructure(){ Id = 1, Hours = 0, Minutes = 30, Seconds = 0 },
new TimerStructure(){ Id = 2, Hours = 1, Minutes = 0, Seconds = 0 }
};
public int Index { get; private set; }
public int Hours { get; set; } = 0;
public int Minutes { get; set; } = 0;
public int Seconds { get; set; } = 0;
public bool StopButtonIsDisabled { get; set; } = true;
public bool StartButtonIsDisabled { get; set; } = false;
private static System.Timers.Timer aTimer;
// and this is the function related to the problem
public void SetTimer(int value)
{
this.Index = value - 1;
Hours = timerCollections[Index].Hours;
Minutes = timerCollections[Index].Minutes;
Seconds = timerCollections[Index].Seconds;
}
public void StopTimer()
{
aTimer.Stop();
aTimer.Dispose();
StopButtonIsDisabled = true;
StartButtonIsDisabled = false;
Console.WriteLine($"{Hours}:{Minutes}:{Seconds}");
}
public void StartTimer() 
{
aTimer = new System.Timers.Timer(1000);
aTimer.Elapsed += CountDownTimer;
aTimer.Start(); 
StopButtonIsDisabled = false;   
StartButtonIsDisabled = true;
}
public void CountDownTimer(Object source, ElapsedEventArgs e)
{
if(Seconds == 0 && Minutes > 0)
{
Minutes -= 1;
Seconds = 59;
} else if (Minutes == 0 && Seconds == 0 && Hours > 0)
{
Hours -= 1;
Minutes = 59;
Seconds = 59;
} else if (Hours == 0 && Minutes == 0 && Seconds == 0)
{
aTimer.Stop();
aTimer.Dispose();
StopButtonIsDisabled = true;
StartButtonIsDisabled = false;
} else
{
Seconds -= 1;
}
InvokeAsync(StateHasChanged);
}
}
}

Answer 1

尝试：<button @onclick="() => SetTimer(timer.Id)">