在C#中制作一个简单的计时器 [英] making a simple timer in C#

问题描述

我还是c#的新手，我不知道如何每十秒调用一次updateTime()

I'm still new to c# and i dont how to invoke the method updateTime() every ten seconds

public class MainActivity : Activity
{
    TextView timerViewer;
    private CountDownTimer countDownTimer;

    protected override void OnCreate (Bundle bundle)
    {
        base.OnCreate (bundle);
        SetContentView (Resource.Layout.Main);

        timerViewer = FindViewById<TextView> (Resource.Id.textView1);

        // i need to invoke this every ten seconds
        updateTimeinViewer();
    }

    protected void updateTimeinViewer(){
        // changes the textViewer
    }
}

如果有一种方法可以创建一个新的线程或类似的东西，我将寻求帮助.

if there's a way to create a new Thread or something similar, i would be please to get some help.

我正在使用Xamarin Studio

I'm using Xamarin Studio

推荐答案

1 -在C#中执行此操作的一种常用方法是使用

1 - One usual way to do that in C# is to use a System.Threading.Timer, like so:

int count = 1;
TextView timerViewer;
private System.Threading.Timer timer;

protected override void OnCreate(Bundle bundle)
{
    base.OnCreate(bundle);
    SetContentView(Resource.Layout.Main);

    timerViewer = FindViewById<TextView>(Resource.Id.textView1);

    timer = new Timer(x => UpdateView(), null, TimeSpan.FromSeconds(10), TimeSpan.FromSeconds(10));
}

private void UpdateView()
{
    this.RunOnUiThread(() => timerViewer.Text = string.Format("{0} ticks!", count++));
}

请注意，在访问UI元素时，您需要使用 Activity.RunOnUiThread()以避免跨线程冲突.

Notice that you need to use Activity.RunOnUiThread() in order to avoid cross-thread violations when accessing UI elements.

2 -另一种更清洁的方法是利用C#的

2 - Another, cleaner approach is to make use of C#'s Language-level support for asynchrony, which removes the need to manually marshal back and forth to the UI thread:

    protected override void OnCreate(Bundle bundle)
    {
        base.OnCreate(bundle);
        SetContentView(Resource.Layout.Main);

        timerViewer = FindViewById<TextView>(Resource.Id.textView1);

        RunUpdateLoop();
    }

    private async void RunUpdateLoop()
    {
        int count = 1;
        while (true)
        {
            await Task.Delay(1000);
            timerViewer .Text = string.Format("{0} ticks!", count++);
        }
    }

请注意，此处不需要 Activity.RunOnUiThread().C#编译器会自动发现这一点.

Notice there's no need for Activity.RunOnUiThread() here. the C# compiler figures that out automatically.

这篇关于在C#中制作一个简单的计时器的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！