Question

使用Ionic2存储，我在自定义提供程序中完成了以下操作，我可以确认键值对已设置，我可以单独检索它们：

class Program
{
    static void Main(string[] args) => Task.Run(() => MainAsync(args)).Wait();

    static async Task MainAsync(string[] args)
    {
        var html = await GetResponseFromURI(new Uri("http://www.dailymail.co.uk/sciencetech/article-4408856/Samsung-building-flip-phone-TWO-screens.html?ITO=1490&ns_mchannel=rss&ns_campaign=1490"));
        HtmlDocument doc = new HtmlDocument();
        doc.LoadHtml(html);
        var nodes = doc.DocumentNode.SelectNodes("//div[@itemprop=\"articleBody\"]");
        if (nodes != null)
        {
            Console.WriteLine(nodes.Select(node => node.InnerText).FirstOrDefault());
        }
        Console.ReadLine();
    }

    static async Task<string> GetResponseFromURI(Uri uri)
    {
        var response = "";
        using (var client = new HttpClient())
        {
            HttpResponseMessage result = await client.GetAsync(uri);
            if (result.IsSuccessStatusCode)
                response = await result.Content.ReadAsStringAsync();
        }
        return response;
    }
}

问题是我的一个页面中有一个函数需要访问HTTP请求的所有这三个值，所以我可以这样得到其中一个：

itemprop=\"articleBody\"

但是如何一次获得多个键值？我是否需要嵌套这些调用，或者是否有一种更简单的方法可以在一次调用中访问多个键，以便我可以执行以下操作：

this.storage.set('one', 1);
this.storage.set('two', 2);
this.storage.set('three', 3);

Answer 1

我为此目的使用了Promise.all

Promise.all([this.storage.get("email"), this.storage.get("username")]).then(values => {

      console.log("email", values[0]);
      console.log("username", values[1]);

      // every other thing can happen here e.g call a method

});

Answer 2

您可以按照以下所示进行操作。

this.storage.forEach( (value, key, index) => {
    console.log("value", value);//store these values as you wish
    console.log("key", key);
    console.log("Index" index);
})

From Api Doc.

 /**
   * Iterate through each key,value pair.
   * @param iteratorCallback a callback of the form (value, key, iterationNumber)
   * @return Promise that resolves when the iteration has finished.
   */

  forEach(iteratorCallback: (value: any, key: string, iterationNumber: Number) => any): Promise<null> {
    return this._dbPromise.then(db => db.iterate(iteratorCallback));
  }

从Ionic2存储中获取多个键值

2 个答案: