Question

我有一个问题，我似乎无法弄清楚我的WindowsPhone 8.1应用程序。在我的客户端，我正在编写代码来从我查询的数据库中检索值。虽然我能够成功地使用我的Bars实体，但我似乎无法让我的团队实体工作。奇怪的是，它似乎已经过去并且卡在我的HttpResponseMessage对象的创建上。这是代码：

private void refresh_Click(object sender, RoutedEventArgs e)
    {
        GetTeams();
        //getTeamById(10);
    }


    public async void GetTeams()
    {
        using (var client = new HttpClient())
        {
            teamsListBox.Items.Add("using block entered");
            client.BaseAddress = new Uri("http://nflff.azurewebsites.net");
            client.DefaultRequestHeaders.Accept.Clear();
            client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
            teamsListBox.Items.Add("client's defaultrequestheaders done");

            HttpResponseMessage response = await client.GetAsync("api/bars");//not getting past here
            teamsListBox.Items.Add("right after response"); //not printing
            if (response.IsSuccessStatusCode)
            {
                teamsListBox.Items.Add("if entered");
                //IList<Teams> Teams = await response.Content.ReadAsAsync<IList<Teams>>();
                string teams = await response.Content.ReadAsStringAsync();

                int start = 0;
                while (start != -1)
                {
                    start = stringToTeam(teams, start); //throwing exception inside stringToTeams, which isn't being called anywhere else
                }
            }
            teamsListBox.Items.Add(Teams.TeamsList.Count);
            foreach (var team in Teams.TeamsList)
            {
                teamsListBox.Items.Add(team.ToString());
            }
        }
    }

public int stringToTeam(String Team, int start)
    {
        start = Team.IndexOf("TeamID", start) + 8;
        int end = Team.IndexOf(",", start); //start index correct
        //teamsListBox.Items.Add(end);
        int id = Convert.ToInt32(Team.Substring(start, end - start)); //throws FormatException for string to DateTime
        //String id = Team.Substring(start, (end - start));
        teamsListBox.Items.Add("id is " + id);
        start = Team.IndexOf("TeamName", start) + 11;
        end = Team.IndexOf("\"", start);
        //teamsListBox.Items.Add(end);
        String name = Team.Substring(start, (end - start));
        teamsListBox.Items.Add("name is " + name);

        String city = Team.Substring(start, (end - start));
        teamsListBox.Items.Add("city is " + city);
        start = Team.IndexOf("TeamState", start) + 12;
        end = Team.IndexOf("\"", start);
        //teamsListBox.Items.Add(end);


        //creates a Teams model obj with values pulled from string and adds it to static list of objs in Teams model
        //teamsListBox.Items.Add(Teams.TeamsList.Count);
        Teams newTeam = new Teams(id, name, city);
        Teams.TeamsList.Add(newTeam);
        //teamsListBox.Items.Add(Teams.TeamsList.Count);
        //teamsListBox.Items.Add(newTeam.ToString());

        end += 4;
        if (end <= Team.Length)
        {
            return end;
        }
        else
        {
            return -1;
        }
    }

当我运行此代码时，“响应后”不会打印到UI，而上面的测试消息是。此外，模拟器最终会破坏并从stringToTeam中的一行（我将发布另一个问题）中抛出一个FormatException，这在其他任何地方都没有被调用。还值得一提的是，我的Bars实体具有完全相同的代码（当然切换名称），并且条形图完全正常。我已经比较了这些方法中的每一行代码以及模型和服务器端控制器，它们完全相同。那么为什么条形码代码可以工作而团队代码却没有呢？

如果有帮助，这是我的型号代码：

public class Teams
{
    private int teamID { get; set; }
    private string teamName { get; set; }
    private string teamCity { get; set; }
    //private object teamFlag { get; set; } //Janci, I was never able to see your comments.  What is teamFlag?  Is that their logo?
    public static List<Teams> TeamsList = new List<Teams>();

    public Teams(int id, string name, string city)
    {
        teamID = id;
        teamName = name;
        teamCity = city;
    }

    public override string ToString()
    {
        return "Team: " + teamID.ToString() + " " + teamName.ToString() + " City: " + teamCity;
    }
}

我在Azure网站上托管了一个SQL数据库，我在后端使用.NET。请帮我弄清楚为什么我的团队代码不起作用。感谢。

Answer 1

我认为问题在于：

HttpResponseMessage response = await client.GetAsync("api/bars");

不应该是：

HttpResponseMessage response = await client.GetAsync("api/teams");

Answer 2

问题结果是我在stringToTeam方法中有错误的开始和结束索引。一旦我修复了它，代码就可以正常工作和显示。方法的IndexOf和Substring调用应如下所示：

        start = Team.IndexOf("TeamID", start) + 8;
        int end = Team.IndexOf(",", start); //start index correct
        //teamsListBox.Items.Add(end);
        int id = Convert.ToInt32(Team.Substring(start, end - start)); //throws FormatException for string to DateTime
        //String id = Team.Substring(start, (end - start));
        //teamsListBox.Items.Add("id is " + id);
        start = Team.IndexOf("TeamName", start) + 11;
        end = Team.IndexOf("\"", start);
        //teamsListBox.Items.Add(end);
        String name = Team.Substring(start, (end - start));
        //teamsListBox.Items.Add("name is " + name);
        start = Team.IndexOf("TeamCity", start) + 11;
        end = Team.IndexOf("\"", start);
        String city = Team.Substring(start, (end - start));

在对我自己的反序列化器进行手工编码并为每个实体调整它之后，我发现了JsonConvert类。我强烈建议您不要编写自己的解串器。使用JsonConvert，我可以删除我的stringToTeam（）方法并用以下内容替换旧的GetTeams（）：

public async void GetTeams()
    {
        using (var client = new HttpClient())
        {
            client.BaseAddress = new Uri("http://nflff.azurewebsites.net");
            client.DefaultRequestHeaders.Accept.Clear();
            client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

            HttpResponseMessage response = await client.GetAsync("api/teams");//not getting past here

            if (response.IsSuccessStatusCode)
            {
                string s = await response.Content.ReadAsStringAsync();
                var deserializedResponse = JsonConvert.DeserializeObject<List<Teams>>(s);
                foreach (Teams team in deserializedResponse)
                {
                    teamsListBox.Items.Add(team.ToString());
                }

            }
            foreach (var team in Teams.TeamsList)
            {
                teamsListBox.Items.Add(team.ToString());
            }
        }
    }

这种方法不那么乏味。

WP8.1客户端代码中的HttpResponseMessage错误

2 个答案: