如何将数据绑定到Xaml，Windows Phone？ [英] How can I bind data into Xaml, Windows Phone?

问题描述

这是我的C＃代码，现在它在控制台中显示数据。

This is my C# code, now it's showing data in console.

class PlaceViewModel
    {

        public List<Vantaa.IntroPage.Place> Places;
    }       

public class Place
            {
                public string id { get; set; }
                public string title { get; set; }
                public string latitude { get; set; }
                public string longitude { get; set; }
                public string www { get; set; }
            }

        public class RootObject
        {
            public List<Place> Places { get; set; }
        }

    protected override void OnNavigatedTo(NavigationEventArgs e)
        {
            WebClient webClient = new WebClient();
            webClient.DownloadStringCompleted += new DownloadStringCompletedEventHandler(webClient_DownloadStringCompleted);
            webClient.DownloadStringAsync(new Uri("http://mobiilivantaa.lightscreenmedia.com/api/place"));
        }

        private void webClient_DownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e)
        {
            var rootObject = JsonConvert.DeserializeObject<RootObject>(e.Result);

            foreach (var book in rootObject.Places)
            {
                System.Diagnostics.Debug.WriteLine(book.id);
            }
            this.DataContext = new PlaceViewModel
                 {
                      Places = rootObject.Places
                 };
            }

为了在textblock中显示数据，我应该如何处理xaml文件？

What should I do with xaml file in order to show the data in textblock ?

这是我目前的xaml代码。这肯定不行。我真的不知道。

This is my current xaml code. It's surely not working. I really have no idea.

<ListBox ItemsSource="{Binding Places}">
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <Grid>
                        <TextBlock Text="{Binding Path=id}" />
                    </Grid>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>

推荐答案

你的类代码看起来不错，现在只是一个将结果束缚于观点的事项。您正在返回对象列表，因此您应该使用支持显示多个项目的控件。当然，您可以将所有图书的id连接到一个字符串，并将其显示在标签中。但这不是怎么做的。您应该做的是将一个ListBox控件添加到XAML并在其中创建一个DataTemplate。这样，您可以设置项目的显示方式。

Your class-code looks good so now it's just a matter of binding the results to the view. You are returning a list of objects so you should use a control that supports showing multiple items. Of course you could concatenate all the id's of the books to one string and show it in a label. But this is not how it's done. What you should do is add a ListBox control to the XAML and create a DataTemplate inside it. This way you set the way items will be displayed.

创建一个类，将作为您的XAML页面的ViewModel。该类将具有属性地方（类型：列表< Place> ）。在获取所有数据完成后的OnNavigatedTo事件中，填写ViewModel并将其绑定到XAML的DataContext：

Create a class that will be the ViewModel for your XAML-page. This class will have a property 'Places' (type: List<Place>). In the OnNavigatedTo-event when getting all the data is done, fill the ViewModel and bind and bind it to the DataContext of the XAML:

this.DataContext = new YourViewModel { Places = rootObject.Places };

这样可以从XAML中的ViewModel中获取所有对象：

This way you can grab all the objects from the ViewModel in your XAML:

<ListBox ItemsSource="{Binding Places}">
    <ListBox.ItemTemplate>
        <DataTemplate>
            <Grid>
                <TextBlock Text="{Binding Path=id}" />
            </Grid>
        </DataTemplate>
    </ListBox.ItemTemplate>
</ListBox>

编辑：

这是一个工作示例：

XAML：

<Grid>
    <ListBox ItemsSource="{Binding Places}">
        <ListBox.ItemTemplate>
            <DataTemplate>
                <StackPanel Orientation="Horizontal">
                    <TextBlock Text="{Binding Path=ID}" />
                    <TextBlock Text="{Binding Path=Title}" />
                </StackPanel>
            </DataTemplate>
        </ListBox.ItemTemplate>
    </ListBox>
</Grid>

Place.cs

public class Place
{
    public string ID { get; set; }
    public string Title { get; set; }
    public string Latitude { get; set; }
    public string Longitude { get; set; }
    public string Web { get; set; }
}

MainViewModel.cs：

public class MainViewModel
{
    public MainViewModel()
    {
        Places = new List<Place>();
    }

    public List<Place> Places { get; set; }
}

样本库（您应该拥有自己的）：

public static List<Place> FetchData()
{
    var lst = new List<Place>();

    lst.Add(new Place { ID = "1", Title = "One", Latitude = "111", Longitude = "111", Web = "www......" });
    lst.Add(new Place { ID = "2", Title = "Two", Latitude = "222", Longitude = "222", Web = "www......" });
    lst.Add(new Place { ID = "3", Title = "Three", Latitude = "333", Longitude = "333", Web = "www......" });
    lst.Add(new Place { ID = "4", Title = "Four", Latitude = "444", Longitude = "444", Web = "www......" });

    return lst;
}

MainWindow.xaml.cs：

public MainWindow()
{
    InitializeComponent();
    //This is where the magic happens
    //Fill the viewModel with the data
    var viewModel = new MainViewModel { Places = Repository.FetchData() };
    //Assign the viewModel with the data to the DataContext
    //The bindings will be automatically done in the XAML
    DataContext = viewModel;
}

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