wpf绑定到客户端不显示名称

Question

我创建了一个简单的解决方案，试图创建一个“客户”，当应用程序运行时，客户名称会出现在 UI 的文本框中。为什么绑定属性并设置datacontext后似乎不显示？

MainWindowViewModel.cs

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using WpfApplication1.Model;

namespace WpfApplication1
{
    class MainWindowViewModel
    {
        private Customer client = new Customer();

        public MainWindowViewModel()
        {
            client.Name = "Greg Johnson";
            client.Friends = new ObservableCollection<string>() { "Leslie", "Mitch" };
        }
    }
}

XAML

    <Window x:Class="WpfApplication1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:viewModel="clr-namespace:WpfApplication1"
        Title="MainWindow" Height="300" Width="305">

    <Window.DataContext>
        <viewModel:MainWindowViewModel />
    </Window.DataContext>

    <Grid>
        <TextBox Text="{Binding Name}"/>
    </Grid>
</Window>

Answer 1

您需要在 View 模型中添加 Client 的属性。然后在绑定中更改为Client.Name。参考下面的代码。

class MainWindowViewModel
{
    public Customer Client { get; set; }

    public MainWindowViewModel()
    {
        Client = new Customer();
        Client.Name = "Greg Johnson";
        Client.Friends = new ObservableCollection<string>() { "Leslie", "Mitch" };
    }
}

<Window.DataContext>
    <viewModel:MainWindowViewModel />
</Window.DataContext>

<Grid>
    <TextBox Text="{Binding Client.Name}"/>
</Grid>

Answer 2

这里有一个概念错误。绑定到 xaml 代码的每个属性必须是：

1. 依赖属性here is the information。
2. 实现 INotifyPropertyChange 接口 here is the information。

只有这样，binnding 才能按您希望的方式工作。 1.Xaml：

<Window x:Class="NirHelpingOvalButton.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:nirHelpingOvalButton="clr-namespace:NirHelpingOvalButton"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
    mc:Ignorable="d"
    Title="MainWindow" Height="350" Width="525">
<Window.DataContext>
    <nirHelpingOvalButton:MainWindowViewModel />
</Window.DataContext>

<Grid>
    <TextBox Text="{Binding Client.Name}" HorizontalAlignment="Center" VerticalAlignment="Center"/>
</Grid></Window>

2。查看模型：

public class MainWindowViewModel:BaseObservableObject
{
    public MainWindowViewModel()
    {
        Client = new Customer
        {
            Name = "Steve",
            Friends = new ObservableCollection<string>(new List<string> {"John", "Alex", "Yakov"})
        };
    }

    private Customer _customer;

    public Customer Client
    {
        get { return _customer; }
        set
        {
            _customer = value;
            OnPropertyChanged();
        }
    }
}

3。型号代码：

public class Customer:BaseObservableObject
{
    private string _name;

    public string Name
    {
        get { return _name; }
        set
        {
            _name = value;
            OnPropertyChanged();
        }
    }

    public ObservableCollection<string> Friends { get; set; }
}

4。 BaseObservableObject 代码：

public class BaseObservableObject : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;

    protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
    {
        var handler = PropertyChanged;
        if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
    }

    protected virtual void OnPropertyChanged<T>(Expression<Func<T>> raiser)
    {
        var propName = ((MemberExpression)raiser.Body).Member.Name;
        OnPropertyChanged(propName);
    }

    protected bool Set<T>(ref T field, T value, [CallerMemberName] string name = null)
    {
        if (!EqualityComparer<T>.Default.Equals(field, value))
        {
            field = value;
            OnPropertyChanged(name);
            return true;
        }
        return false;
    }
}

5。它的样子：

问候，