我试图在Windows 8中使用MVVM设计模式做一个简单的测验程序。我试图使用PRISM和MVVMlite,但是我是一个新手,根本没有足够的数据和控制绑定知识来理解如何正确使用它。我认为我的大部分工作正在进行,但我有一些主要问题。 1.我的GUI不能正确更新。 2.我收到几个错误。 3.修复我的代码的一部分打破了另一部分。 4.无法弄清楚如何从XAML中的命令获取“发件人”信息。Windows 8 C#到XAML数据绑定问题,GUI不更新
这里是到目前为止我的代码:
XML数据:
<root>
<Object>
<Question>What do you do for work</Question>
<Answer>Wrestle giant tentical monsters</Answer>
<Choices>Battle robots</Choices>
<Choices>Glorious ruler of North Korea</Choices>
<Choices>Wrestle Giant Tentical Monsters</Choices>
<Choices>Defender of all that is good</Choices>
</Object>
<Object>
<Question>What do you drive</Question>
<Answer>Moped</Answer>
<Choices>Helicopter</Choices>
<Choices>Pegasus</Choices>
<Choices>Rocketship</Choices>
<Choices>Moped</Choices>
</Object>
</root>
型号:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.ComponentModel;
using System.Xml.Linq;
using System.Windows.Input;
namespace Quiz
{
class QuizModel : INotifyPropertyChanged
{
private string _question;
public string Question
{
get { return _question; }
set
{
_question = value;
OnPropertyChanged("Question");
}
}
private string _answer;
public string Answer
{
get { return _answer; }
set
{
_answer = value;
OnPropertyChanged("Answer");
}
}
private List<string> _choices;
public List<string> Choices
{
get { return _choices; }
set
{
_choices = value;
OnPropertyChanged("Choices");
}
}
public QuizModel(string quesiton, string answer, List<string> choices)
{
Question = quesiton;
Answer = answer;
Choices = choices;
}
public static List<QuizModel> Query(string datasource)
{
XElement quizdata = XElement.Load(datasource);
List<QuizModel> query = (from d in quizdata.Descendants("Object")
select new QuizModel(
(string)d.Element("Question"),
(string)d.Element("Answer"),
d.Elements("Choices").Select(a => a.Value).ToList()
)).ToList();
return query;
}
public event PropertyChangedEventHandler PropertyChanged;
public void OnPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
}
视图模型:
class QuizViewModel
{
public static List<QuizModel> QuizList { get; set; }
public static QuizModel Quiz { get; set; }
public static int Indexer { get; set; }
public ICommand myCommand { get; set; }
//Initiallizes view model
public QuizViewModel()
{
Indexer = 0;
QuizList = QuizModel.Query("Quiz.xml");
Quiz = QuizList[Indexer];
myCommand = new ActionCommand(Evaluate);
}
//Increments to next question
private void Evaluate()
{
Indexer++;
Quiz = QuizList[Indexer];
}
}
的ICommand:
public class ActionCommand : ICommand
{
private readonly Action _action;
public ActionCommand(Action action)
{
_action = action;
}
public void Execute(object parameter)
{
_action();
}
public bool CanExecute(object parameter)
{
return true;
}
public event EventHandler CanExecuteChanged; //ERROR event Never Used
}
}
检视:
<Grid Background="{StaticResource ApplicationPageBackgroundThemeBrush}">
<Grid.RowDefinitions>
<RowDefinition Height="1*"/>
<RowDefinition Height="3*"/>
</Grid.RowDefinitions>
<TextBlock FontSize="50" Text="{Binding Quiz.Question}">
<TextBlock.DataContext>
<local:QuizViewModel/> <!--Can't find Quiz.xml-->
</TextBlock.DataContext>
</TextBlock>
<ListView Grid.Row="1" FontSize="30" ItemsSource="{Binding Quiz.Choices}">
<ListView.DataContext>
<local:QuizViewModel/> <!--Can't find Quiz.xml-->
</ListView.DataContext>
<ListView.ItemTemplate>
<DataTemplate>
<Button Content="{Binding Mode=OneWay}" Command="{Binding myCommand}">
<Button.DataContext>
<local:QuizViewModel/>
</Button.DataContext>
</Button>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</Grid>
我有3个电流误差2,其是相同的 第一个错误是指在XAMLs的datacontext:
错误1(×2)
找不到文件'C:\ Users \ Me \ AppData \ Local \ Microsoft \ VisualStudio \ 11.0 \ Designer \ ShadowCache \ cv0te54x.fpv \ 5ncl4yxi.hui \ Quiz.xml'。
错误2 无法创建类型为“Quiz.QuizViewModel”
这似乎影响了我的“选择”不填充,我可以通过删除数据方面解决这个问题,但我不能结合“的实例myCommand“
第三个问题是我如何从命令输入发件人信息,以便我可以评估它是对还是错?
那么它最初填充,它只是不会更新到下一个选择。我试图让这条路更加具体,但是当我这样做的时候,它抛出了许多错误。我现在把它设置为内容,我尝试了嵌入式资源,但这并不起作用。我会尝试你的想法来解决第三个问题。谢谢 – evilsushi
任何关于如何使我的路径更具体的“Quiz.xml”的建议。它目前在源代码目录中,所以我没有办法让它更具体。 – evilsushi