Question

我的Wpf Apllication中的代码行有问题。label.Content = (string)nextfruit["q_text"];我收到此错误（类型＆＃34;字符串＆＃34;无法隐式转换为＆＃34; System.Windows。 Controls.Label＆＃34;）我认为这应该按照我的方式工作。

有我的代码

using System;
using System.IO;
using System.Net;
using System.Windows;
using System.Web.Script.Serialization;
using System.Collections.Generic;
using Newtonsoft.Json;
using System.Json;
using System.Linq;
using Newtonsoft.Json.Linq;

 namespace MMPI2_Test
  {
    /// <summary>
   /// Interaktionslogik für Patient.xaml
   /// </summary>
 public partial class Patient : Window
{
    public Patient()
    {
        InitializeComponent();
        Loaded += MyWindow_Loaded;
    }


    public String MyProperty { get; set; }

    public String Property { get; set; }

    private IEnumerator<JObject> Enumerator { get; set; }
    public bool HasNext { get; private set; }




    private void MyWindow_Loaded(object sender, RoutedEventArgs e)
    {
        dynamic convert = JsonConvert.DeserializeObject(MyProperty);

        string user = MyProperty;
        //lbuser.Content = json;


       //string tan = "";
        MainWindow main = new MainWindow();
        // main.alpha = tan;

        string html = string.Empty;
        string url = @"http://stidl.workcloud.at/?tag=question&token=" + Property;

        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
        request.AutomaticDecompression = DecompressionMethods.GZip;

        using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
        using (Stream stream = response.GetResponseStream())
        using (StreamReader reader = new StreamReader(stream))
        {
            html = reader.ReadToEnd();
        }
        // dynamic magic = JsonConvert.DeserializeObject(html);
        // string json2 = new JavaScriptSerializer().Serialize(html);


        var j = new JavaScriptSerializer().DeserializeObject(user) as Dictionary<string, object>;
        var d = j["data"] as Dictionary<string, object>;
        lbuser.Content = d["fname"] + " " + d["lname"].ToString();

        //JObject QuestionObject = JObject.Parse(html);
        //JToken question = QuestionObject["data"].First["q_text"];
        //lbquestion.Content = question;

        JObject QuestionObject = JObject.Parse(html);
        Enumerator = QuestionObject["data"].Children<JObject>().GetEnumerator();

        JObject IDObject = JObject.Parse(html);
        JToken id = IDObject["data"].First["q_id"];
        JToken lastid = IDObject["data"].Last["q_id"];
        //JToken nextid = IDObject["data"].First.Next.Next["q_id"];
        lbid.Content = "Frage " + id + " von " + lastid;


    }

    class qq
    { 

    }

    private void bt_no_Click(object sender, RoutedEventArgs e)
    {

        string html = string.Empty;
        string url = @"http://stidl.workcloud.at/?tag=question&token=" + Property;

        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
        request.AutomaticDecompression = DecompressionMethods.GZip;

        using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
        using (Stream stream = response.GetResponseStream())
        using (StreamReader reader = new StreamReader(stream))
        {
            html = reader.ReadToEnd();
        }
        //JObject IDObject = JObject.Parse(html);
        //JToken nextid = IDObject["data"].First["q_id"];
        ////int result = (int)nextid;
        //lbid.Content = nextid;

        HasNext = Enumerator.MoveNext();
        if (HasNext)
        {
            JObject QuestionObject = JObject.Parse(html);
            Enumerator = QuestionObject["data"].Children<JObject>().GetEnumerator();
            JObject nextfruit = Enumerator.Current;
            lbquestion = (string)nextfruit["q_text"];
        }
        else
        {

        }


    }

    private void bt_yes_Click(object sender, RoutedEventArgs e)
    {

    }

    //public class QuestionData
    //{
    //    public string Data { get; set; } // this will store the JSON string
    //    public List<Data> DataList { get; set; } // this will be the actually list. 
    //}

    //public class Data
    //{
    //    public string q_id { get; set; }
    //    public string q_text { get; set; }


    //}


 }
}

我的XML代码

<Window x:Class="MMPI2_Test.Patient"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:local="clr-namespace:MMPI2_Test"
    mc:Ignorable="d"
    Title="Patient" Height="560" Width="980">
<Window.Background>
    <ImageBrush ImageSource="images/background.jpg" />
</Window.Background>

<Grid>
    <Label x:Name="lbquestion" Content="" HorizontalAlignment="Left" Margin="31,229,0,0" VerticalAlignment="Top" Width="906" Height="71"/>
    <Button x:Name="bt_yes" Content="Ja" HorizontalAlignment="Left" Margin="534,349,0,0" VerticalAlignment="Top" Width="75" Click="bt_yes_Click" />
    <Button x:Name="bt_no" Content="Nein" HorizontalAlignment="Left" Margin="389,349,0,0" VerticalAlignment="Top" Width="75" Click="bt_no_Click"/>
    <Label x:Name="lbuser" Content="" HorizontalAlignment="Left" Height="73" Margin="31,151,0,0" VerticalAlignment="Top" Width="906"/>
    <Label x:Name="lbid" Content="" HorizontalAlignment="Left" Height="50" Margin="31,69,0,0" VerticalAlignment="Top" Width="783"/>

</Grid>

Answer 1

if (HasNext)
    {
        JObject QuestionObject = JObject.Parse(html);
        Enumerator = QuestionObject["data"].Children<JObject>().GetEnumerator();
        JObject nextfruit = Enumerator.Current;
        lbquestion = (string)nextfruit["q_text"]; //lbquestion is a label
    }

在我看来，这应该是设置内容。这甚至是你在问题中所说的。

Answer 2

更新：我错过了lbQuestion是一个标签。

(string)nextfruit["q_text"]是一个强制转换字符串的尝试。如果您要转换为字符串，则需要访问lbQuestion.Content;错误告诉您，您正在尝试将标签等同为字符串，而不是。

字符串无法转换为System.Windows.Control.Label

2 个答案: