如何填充文本框-Windows Phone 8.1

Posted 2023-04-12

【中文标题】如何填充文本框-Windows Phone 8.1

【英文标题】：How to populate textboxes-Windows Phone 8.1

【发布时间】：2016-07-30 07:26:07

【问题描述】：

当从另一个 xaml（菜单）中选择项目时，我要做的基本上是在一个 xaml（篮子）中使用项目名称填充文本框。我的代码如下：

Menu.xaml

在这里，当我单击一个按钮时，我希望它自动出现在 Basket.xaml 的文本框中。

    public class PassedData
    
        public string Name  get; set; 
        public int Value  get; set; 
    
    private void Vanbtn_Click(object sender, RoutedEventArgs e)
    


        Frame.Navigate(typeof(Basket), new PassedData  Name = "Cheese" );
    

    private void LCbtn_Click(object sender, RoutedEventArgs e)
    
        Frame.Navigate(typeof(Basket), new PassedData  Name = "Crisp" );
    

Basket.xaml

       protected override void OnNavigatedTo(NavigationEventArgs e)
    
        Menu.PassedData data = e.Parameter as Menu.PassedData;
    /**    ItemChosentxt.Text = data.Name;
        ItemChosentxt2.Text = data.Name;
        ItemChosentxt3.Text = data.Name;
        ItemChosentxt4.Text = data.Name;**/


    

注释掉的部分添加了所选项目的名称。而不是只添加到一个文本框，而是添加到所有文本框。即，如果我在 Menu.xaml 中选择 vanilla btn，则名称会出现在所有 4 个文本框中，而不仅仅是一个。所以我决定在每个文本框中实现代码：

private void ItemChosentxt_TextChanged(object sender, TextChangedEventArgs e)
    
        Menu.PassedData data = e.Parameter as Menu.PassedData;
        ItemChosentxt.Text = data.Name;
    

    private void SecItem_TextChanged(object sender, TextChangedEventArgs e)
    
        Menu.PassedData data = e.Parameter as Menu.PassedData;
        SecItem.Text = data.Name;
    

这会在 e.Parameter 下面显示一个错误，错误代码是 -

Severity    Code    Description Project File    Line    Suppression State
    Error   CS0103  The name 'data' does not exist in the current context    

和

    Severity    Code    Description Project File    Line    Suppression State
Error   CS1061  'TextChangedEventArgs' does not contain a definition for 'Parameter' and no extension method 'Parameter' accepting a first argument of type 'TextChangedEventArgs' could be found (are you missing a using directive or an assembly reference?) 

我正在开发一个购物应用程序，例如如果用户从菜单中选择“香草”和“蛋糕”，我怎样才能使名称显示在篮子文本框中？我是应用程序开发的新手，并为这个冗长的问题道歉。

【参考方案1】：

问题是您没有为 TextChangedEventArgs e 提供 PassedData。

编译器专门对你大喊大叫

说 e.Paramenter（TextChangedEventArgs 没有“参数”成员） 用于使用未定义的“数据”，因为 1。

但是，我推荐一种完全不同的方法。只需使用列表视图（和数据绑定）。 例子：

Basket.xaml

<Grid Background="ThemeResource ApplicationPageBackgroundThemeBrush">
    <ListView ItemsSource="Binding PassedData" HorizontalAlignment="Center" VerticalAlignment="Center">
        <ListView.ItemTemplate>
            <DataTemplate>
                <Grid>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="auto"/>
                        <ColumnDefinition Width="auto"/>
                    </Grid.ColumnDefinitions>
                    <Grid.RowDefinitions>
                        <RowDefinition Height="auto"/>
                    </Grid.RowDefinitions>
                    <TextBox Grid.Column="0" Text="Binding Name" />
                    <TextBox Grid.Column="1" Text="Binding Value" />
                </Grid>
            </DataTemplate>
        </ListView.ItemTemplate>
    </ListView>
</Grid>

Basket.xaml.cs

using System.Collections.ObjectModel;
using System.ComponentModel;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Navigation;

    // namespace ...

public sealed partial class Basket : Page

    private static ObservableCollection<Menu.PassedData> passedData = new ObservableCollection<Menu.PassedData>();
    public ObservableCollection<Menu.PassedData> PassedData
    
        get  return passedData; 
        set  passedData = value; 
    


    /*Events*/

    public event PropertyChangedEventHandler PropertyChanged;

    /*Methods*/

    /// Fires PropertyChangedEventHandler, for bindables
    protected void OnPropertyChanged(string name)
    
        var ev = PropertyChanged;
        if (ev != null)
        
            ev(this, new PropertyChangedEventArgs(name));
        
    

    public Basket()
    
        this.InitializeComponent();
        this.DataContext = this;
    

    protected override void OnNavigatedTo(NavigationEventArgs e)
    
        Menu.PassedData data = e.Parameter as Menu.PassedData;
        /**    ItemChosentxt.Text = data.Name;
            ItemChosentxt2.Text = data.Name;
            ItemChosentxt3.Text = data.Name;
            ItemChosentxt4.Text = data.Name;**/
        if (data != null)
        
            PassedData.Add(data);
        

    

    private void Button_Click(object sender, RoutedEventArgs e)
    
        Frame.Navigate(typeof(Menu));