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c# - 如何使用循环从 c# 中的字符串中提取特定的子字符串？

问题描述

我试图从我从 Web 服务器获得的响应中提取路由号。响应如下所示；

[{"Description":"METRO Blue Line","ProviderID":"8","Route":"901"},{"Description":"METRO Green Line","ProviderID":"8","Route ":"902"},

我只需要获取路线编号，以便我可以用它们填充组合框。我正在尝试使用循环，因为有很多。我当前的解决方案获得了第一个路由号码，但由于某种原因，我之后才获得提供者号码。这就是我到目前为止所拥有的。

        //get bus routes and popluate the busRoutecmb
        restClient.endPoint = routeUrl + formatLine;
        string response = restClient.request();

        //show me what was returned for debug puposes
        System.Diagnostics.Debug.Write(response);

        //sort through data and put relevent item in a list
        List<string> responseItems = new List<string>();
        //splitting into routes
        string[] splitByRoute = response.Split('}');

        //extracting route number from elements in splitByRoute
        List<string> extractedRouteNums = new List<string>();

        foreach (string thing in splitByRoute)
        {
            //splitting each bus route up by piece of information
            string[] splitByWord = thing.Split(',');
            //getting rid of everything but the route number
            int length = splitByWord.Length;
            int count = 2;
            while (count <= length)
            {
                string[] word = splitByWord[count].Split(':');
                string routeNum = word[1].Trim('"');
                count += 3;
                extractedRouteNums.Add(routeNum);
                System.Diagnostics.Debug.WriteLine(count);
                System.Diagnostics.Debug.WriteLine(routeNum);

            }

        }

        //add repsonse to busRoutecmb
        busRoutecmb.DataSource = extractedRouteNums;

    }

标签： c#.netjsonstring-formatting

解决方案

你得到的基本上是一个 JSON 字符串，它只是一个名称值对数组或一个字典列表。

  [{
        "Description": "METRO Blue Line",
        "ProviderID": "8",
        "Route": "901"
    },
    {
        "Description": "METRO Green Line",
        "ProviderID": "8",
        "Route": "902"
    }]

您可以通过多种方式将该字符串反序列化为列表，一种是使用 System.Web.Script.Serialization.JavaScriptSerializer 或 JSON.NET。进入列表后，您可以查询该列表并仅返回路由键、值对。

    var data = "[{ Description:\"METROBlueLine\",ProviderID:\"8\",Route:\"901\"},{Description:\"METRO Green Line\",ProviderID:\"8\",Route:\"902\"}]";

                var ser = new System.Web.Script.Serialization.JavaScriptSerializer();
                var mylist = ser.Deserialize<List<Dictionary<string,string>>>(data);
    //or JSON.net
                var mylist = Newtonsoft.Json.JsonConvert.DeserializeObject<Dictionary<string, string>>(json);

                var routes = mylist.SelectMany(a => a).Where(c => c.Key == "Route").ToList();
                foreach (var route in routes)
                    Console.Write(route);

    output
    [Route, 901][Route, 902]

如果您真的只想要这些值，那么

var routesonly = routes.Select(r => r.Value).ToList();

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