在AndroidManifest.xml文件中添加以下代码以确保你的应用程序在设备启动时启动：

要求启动设备时接收权限以触发“BOOT_COMPLETED”广播，并使用“BootReceiver”来监听广播。 此处是以下代码的示例：

[BroadcastReceiver(Enabled = true, Exported = true)]
[IntentFilter(new[] { Android.Content.Intent.ActionBootCompleted },
Categories = new[] { Android.Content.Intent.CategoryDefault })]
public class BootReceiver : BroadcastReceiver
{
  public override void OnReceive(Context context, Intent intent)
  {
    if (intent.Action == Android.Content.Intent.ActionBootCompleted)
    {
      Intent serviceIntent = new Intent(context, typeof(YourService));
      if (Build.VERSION.SdkInt >= BuildVersionCodes.O)
      {
        context.StartForegroundService(serviceIntent);
      }
      else
      {
        context.StartService(serviceIntent);
      }
    }
  }
}

实现了BroadcastReceiver后，你需要启动应用程序服务。 为了在后台持续运行，你可能需要将服务转换为前台服务，因此添加以下代码：

if (Build.VERSION.SdkInt >= BuildVersionCodes.O)
{
  NotificationChannel notificationChannel = new NotificationChannel(CHANNEL_ID, "YourChannelName", NotificationImportance.Default);
  NotificationManager notificationManager = (NotificationManager)GetSystemService(NotificationService);
  notificationManager.CreateNotificationChannel(notificationChannel);
  NotificationCompat.Builder builder = new NotificationCompat.Builder(this, CHANNEL_ID)
    .SetContentTitle("YourContentTitle")
    .SetContentText("YourContentText")
    .SetPriority(NotificationCompat.PriorityDefault)
    .SetAutoCancel(true)
    .SetSmallIcon(Resource.Drawable.xamarin_logo);
  Notification notification = builder.Build();
  StartForeground(NOTIFICATION_ID, notification);
}

最后，确保启动设备后任何应用程序部署和初始化完全完成。

[Application]
public class CustomApplication : Application
{
  public override void OnCreate()
  {
    // do your initialization here
  }
}