Question

以下代码尝试获取正在运行该代码的计算机的位置：

GeoCoordinateWatcher watcher = new GeoCoordinateWatcher(GeoPositionAccuracy.High);
if (watcher.TryStart(false, TimeSpan.FromMilliseconds(3000)))
{
    GeoCoordinate coord = watcher.Position.Location;
    if (!coord.IsUnknown)
    {
        Printer.Print(String.Format("Current Lat: {0}, Current Long: {1}", coord.Latitude, coord.Longitude));
    }
    else // Path taken most often
    {
        throw new CommandException("Weather data unknown. (Are location services enabled?)"); 
    }
}
else
{
    throw new CommandException("Weather data unknown. (Are location services enabled?)");
}

每隔一段时间，都会打印出正确的位置，但是在大多数情况下，运行注释的else语句。经过多次测试，我意识到它是否有效完全是随机的。我做错了吗？

Answer 1

您遇到问题的原因可能是您正在初始化新的定位器，而不是等待状态报告状态为已就绪，然后再检查位置。

bool abort = false;
GeoCoordinateWatcher watcher = new GeoCoordinateWatcher(GeoPositionAccuracy.High);
if (watcher.TryStart(false, TimeSpan.FromMilliseconds(3000)))
{
    DateTime start = DateTime.Now;
    while(watcher.Status != GeoPositionStatus.Ready && !abort)
    {
        Thread.Sleep(200);
        if(DateTime.Now.Subtract(start).TotalSeconds > 5)
            abort = true;
    }

    GeoCoordinate coord = watcher.Position.Location;
    if (!coord.IsUnknown)
    {
        Printer.Print(String.Format("Current Lat: {0}, Current Long: {1}", coord.Latitude, coord.Longitude));
    }
    else // Path taken most often
    {
        throw new CommandException("Weather data unknown. (Are location services enabled?)"); 
    }
}
else
{
    throw new CommandException("Weather data unknown. (Are location services enabled?)");
}

基本上，这会添加检查以查看状态是否就绪，并最多等待5秒钟。

或者，通常应将监视程序设置为模块级别并注册PositionChanged事件，以便仅在位置实际更改时更新打印输出，而不是轮询循环以重复当前操作静止时一次又一次地定位。

GeoCoordinateWatcher仅偶尔运行一次

1 个答案: