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尝试将坐标传递到多维数组时出现问题。抛出的错误：

(1)var newArray = item.To2dArray();在 GetInstructions() 方法中：

List 不包含 To2dArray 的定义，并且没有可扩展的方法 To2dArray 接受类型为 ist 的第一个参数

(2) 在添加public partial class SiteMaster : MasterPage方法时public static Coords[,] To2dArray(this List<List<Coords>> list)

扩展方法必须在非泛型静态类中定义

我的列表结构

    public class Route
    {
        public string status_message { get; set; }
        public string route_geometry { get; set; }
        public int status { get; set; }
        //route_instructions is what I'm interested in
        public List<List<object>> route_instructions { get; set; }
    }

    public class Coords
    {
        public int Lat { get; set; }
        public int Lon { get; set; }
        public Coords(string a, string b)
        {
            this.Lat = Convert.ToInt32(a);
            this.Lon = Convert.ToInt32(b);
        }
    }
    List<Coords> Coordinates = new List<Coords>();

反序列化 JSON 的代码

    private void GetInstructions()
    {
            string strurltest = String.Format("https://developers.onemap.sg/privateapi/routingsvc/route?start="+
                        startLat+","+ startLon +"&end="+ destinationLat +","+ destinationLon+"&"+
                        "routeType="+ transportType + "&token="+token);
            WebRequest requestObjGet = WebRequest.Create(strurltest);
            requestObjGet.Method = "GET";
            HttpWebResponse responseObjGet = null;
            responseObjGet = (HttpWebResponse)requestObjGet.GetResponse();
            string strresulttest = null;
            using (Stream stream = responseObjGet.GetResponseStream())
            {
                StreamReader sr = new StreamReader(stream);
                strresulttest = sr.ReadToEnd();
                sr.Close();
            }

            Route route = new JavaScriptSerializer().Deserialize<Route>(strresulttest);
            route_geometry = route.route_geometry;
            //display route instructions

            foreach (var item in route.route_instructions)
            {
                var newArray = item.To2dArray();
                System.Diagnostics.Debug.WriteLine(item[3]);
                TextBox3.Text = TextBox3.Text + Environment.NewLine + item[9];
            }

        }

将列表对象转换为多维数组的代码

public static Coords[,] To2dArray(this List<List<Coords>> list)
    {
        if (list.Count == 0 || list[0].Count == 0)
            throw new ArgumentException("The list must have non-zero dimensions.");

        var result = new Coords[list.Count, list[0].Count];
        for (int i = 0; i < list.Count; i++)
        {
            for (int j = 0; j < list[i].Count; j++)
            {
                if (list[i].Count != list[0].Count)
                    throw new InvalidOperationException("The list cannot contain elements (lists) of different sizes.");
                result[i, j] = list[i][j];
            }
        }

        return result;
    }

打印时的列表对象采用以下格式：（System.Diagnostics.Debug.WriteLine(item[3]);在 GetInstructions() 中时）

1.315396,103.764419
1.314333,103.763455
1.312906,103.766496
1.312109,103.772234
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1 回答 1

1

如果方法是静态的并且在静态类中，则只能将方法用作扩展。您的方法To2dArray必须移动到一个额外的静态类。这就是以下消息的含义：

扩展方法必须在非泛型静态类中定义

另一个问题是，该方法的签名不适合：您正在迭代route.route_instructions所以item是类型List<object>，但您的方法需要List<List<Coords>>

foreach (var item in route.route_instructions)
{
      var newArray = item.To2dArray();
///...
于 2019-10-28T06:35:22.467 回答