DownloadString not getting executed

本文关键字：executed getting not DownloadString | 更新日期: 2023-09-27 17:59:41

我是C#的新手。网络编程面临的一个问题。当我调用getLocation函数时，我总是得到空的"location"。我知道我做事情的方式不对。但如果有人能帮助我以正确的方式去做，那就太好了。我希望getLocation函数返回位置值。因此，它应该只在返回位置值之前执行wc.downloadString时才返回。

public String getLocation()
{
    RetrieveFormatedAddress(latitude, longitutde);
    location = returnVal;
    return location;
}
static void RetrieveFormatedAddress(string lat, string lng)
{
    string requestUri = string.Format(baseUri, lat, lng);
    using (WebClient wc = new WebClient())
    {
        wc.DownloadStringCompleted += new DownloadStringCompletedEventHandler(wc_DownloadStringCompleted);
        wc.DownloadString(new Uri(requestUri));
        //wc.DownloadStringAsync(new Uri(requestUri));
    }
}
private static void wc_DownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e)
{
    var xmlElm = XElement.Parse(e.Result);
    var status = (from elm in xmlElm.Descendants()
                  where elm.Name == "status"
                  select elm).FirstOrDefault();
    if (status.Value.ToLower() == "ok")
    {
        var res = (from elm in xmlElm.Descendants()
                   where elm.Name == "formatted_address"
                   select elm).FirstOrDefault();
        returnVal = res.Value;
    }
    else
    {
        returnVal = "No Address Found";
    }
}

DownloadString not getting executed

public String getLocation()
{
    return RetrieveFormatedAddress(latitude, longitutde);
}
static string RetrieveFormatedAddress(string lat, string lng)
{
    string requestUri = string.Format(baseUri, lat, lng);
    using (WebClient wc = new WebClient())
    {
        var result = wc.DownloadString(new Uri(requestUri));
        var xmlElm = XElement.Parse(result);
        var status = (from elm in xmlElm.Descendants()
              where elm.Name == "status"
              select elm).FirstOrDefault();
        if (status.Value.ToLower() == "ok")
        {
        var res = (from elm in xmlElm.Descendants()
               where elm.Name == "formatted_address"
               select elm).FirstOrDefault();
            return res.Value;
        }
        else
        {
            return "No Address Found";
        }
    }
}

DownloadString()方法是DownloadStringAsync()方法的同步版本。它以字符串形式返回从服务器下载的数据。在您的代码中，您不会在任何地方读取此值。尝试var data = wc.DownloadString(new Uri(requestUri));获取数据。

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