名字“str”当前上下文中不存在

Question

我在这里声明了一个类变量

void downloader_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e)
{
    if (e.Error == null)
    {
        Stream responseStream = e.Result;
        StreamReader responseReader = new StreamReader(responseStream);
        string response = responseReader.ReadToEnd();


        string[] split1 = Regex.Split(response, "},{");
        List<string> pri1 = new List<string>(split1);
        pri1.RemoveAt(0);
        string last = pri1[pri1.Count() - 1];
        pri1.Remove(last);

    }
}

，我想在这个方法中使用类变量 str

void AddPrimaryMarkerGraphics(object sender, getPrimaryListCompletedEventArgs e) 
{
    List<PrimaryClass> primaryList = new List<PrimaryClass>(e.Result);
    PrimaryClass sc = new PrimaryClass();
    for (int a = 0; a <= e.Result.Count - 1; a++)
    {
        string schname = e.Result.ElementAt(a).PrimarySchool;
        string tophonour = e.Result.ElementAt(a).TopHonour;
        string cca = e.Result.ElementAt(a).Cca;
        string topstudent = e.Result.ElementAt(a).TopStudent;
        string topaggregate = e.Result.ElementAt(a).TopAggregate;
        string topimage = e.Result.ElementAt(a).TopImage;

        foreach (string item in str)
        {
            string abc = "[{" + item + "}]";
            byte[] buf = System.Text.Encoding.UTF8.GetBytes(abc);
            MemoryStream ms = new MemoryStream(buf);

            JsonArray users = (JsonArray)JsonArray.Load(ms);

            var members = from member in users
                          //where member["SEARCHVAL"]
                          select member;

            foreach (JsonObject member in members)
            {
                string schname = member["SEARCHVAL"];
                string axisX = member["X"];
                string axisY = member["Y"];
                // Do something...
                string jsonCoordinateString = "{'Coordinates':[{'X':" + axisX + ",'Y':" + axisY + "}]}";
                CustomCoordinateList coordinateList = DeserializeJson<CustomCoordinateList>(jsonCoordinateString);

                GraphicsLayer graphicsLayer = MyMap.Layers["MyGraphicsLayer_Primary"] as GraphicsLayer;

                for (int i = 0; i < coordinateList.Coordinates.Count; i++)
                {
                    Graphic graphic = new Graphic()
                    {
                        Geometry = new MapPoint(coordinateList.Coordinates[i].X, coordinateList.Coordinates[i].Y),
                        Symbol = i > 0 ? PrimarySchoolMarkerSymbol : PrimarySchoolMarkerSymbol

                    };
                    graphic.Attributes.Add("PrimarySchool", schname);
                    graphic.Attributes.Add("xcoord", axisX);
                    graphic.Attributes.Add("ycoord", axisY);
                    graphicsLayer.Graphics.Add(graphic);
                }
            }
        }
    }
}

这就是错误显示的地方。

Answer 1

几乎可以肯定，您已经在方法中声明了变量（即作为本地变量），而不是直接在类本身中声明了该变量（作为实例变量）。例如：

// Wrong
class Bad
{
    void Method1()
    {
        List<string> str = new List<string>();
    }

    void Method2()
    {
        foreach (string item in str)
        {
            ...
        }
    }
}

// Right
class Good
{
    private List<string> str = new List<string>();

    void Method1()
    {
        str = CreateSomeOtherList();
    }

    void Method2()
    {
        foreach (string item in str)
        {
            ...
        }
    }
}

作为旁注：如果您对 C# 非常陌生，我强烈建议您暂时停止使用 Silverlight，并编写一些控制台应用程序来帮助您继续使用，并教你基础知识。这样您就可以专注于 C# 作为一种语言和核心框架类型（例如文本、数字、集合、I/O），然后开始编写 GUI。 GUI 编程通常需要学习很多东西（线程、XAML、绑定等），尝试一次性学习所有内容只会让事情变得更加困难。

Answer 2

它不起作用，因为 str 没有在另一个变量中声明。这是 sscopong 问题。您可以将 str 作为输入传递给另一个函数吗？