c# - 为什么我的 WPF 绑定(bind)实现不能双向工作？

Question

我正在尝试为 WPF 绑定(bind)创建一个模板，以便我可以在将来需要使用绑定(bind)时从中提取代码。目前绑定(bind)不起作用。

我希望此代码在 UI 的文本框中显示“MyString”和“MyInt”，并在用户更改值时正确更改逻辑(因此出现复选按钮)。

但是，MyString 和 MyInt 并未显示在文本框中，更改它们也不会实际更改变量的值。

主窗口.xaml.cs:

using System.Windows;
namespace WpfBindingTemplate
{
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            this.DataContext = this;
            myController = new Controller();
        }

        Controller myController;

        private void check_string(object sender, RoutedEventArgs e)
        {
            MessageBox.Show("MyString: " + myController.MyString);
        }

        private void check_int(object sender, RoutedEventArgs e)
        {
            MessageBox.Show("MyInt: " + myController.MyInt);
        }
    }
}

主窗口.xaml:

<Window x:Class="WpfBindingTemplate.MainWindow"
        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:WpfBindingTemplate"
        mc:Ignorable="d"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <TextBox Name="myTextBox" Text="{Binding Path=myController.MyString}" HorizontalAlignment="Left" Height="23" Margin="202,136,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="120"/>
        <Label x:Name="label" Content="String binding:" HorizontalAlignment="Left" Margin="77,133,0,0" VerticalAlignment="Top" Width="104"/>
        <Button x:Name="button" Content="string check" Click="check_string" HorizontalAlignment="Left" Margin="370,136,0,0" VerticalAlignment="Top" Width="75"/>
        <Label x:Name="label1" Content="int binding:" HorizontalAlignment="Left" Margin="77,188,0,0" VerticalAlignment="Top" Width="94"/>
        <TextBox x:Name="textBox" Text="{Binding Path=myController.MyInt}" HorizontalAlignment="Left" Height="23" Margin="202,190,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="120"/>
        <Button x:Name="button1" Click="check_int" Content="int check" HorizontalAlignment="Left" Margin="370,188,0,0" VerticalAlignment="Top" Width="75"/>
    </Grid>
</Window>

Controller 类:

using System.Collections.Generic;
using System.ComponentModel;
using System.Runtime.CompilerServices;

namespace WpfBindingTemplate
{
    public class Controller : INotifyPropertyChanged
    {
        public Controller()
        {
            MyString = "test string";
            MyInt = 1;
        }

        public int MyInt { get; set; }

        private string myString;
        public string MyString { get { return myString; } set { SetProperty(ref myString, value); } }


        public event PropertyChangedEventHandler PropertyChanged;
        private void SetProperty<T>(ref T field, T value, [CallerMemberName] string name = "")
        {
            if (!EqualityComparer<T>.Default.Equals(field, value))
            {
                field = value;
                var handler = PropertyChanged;
                if (handler != null)
                {
                    handler(this, new PropertyChangedEventArgs(name));
                }
            }
        }
    }
}

Answer 1

对于初学者来说，绑定(bind)对字段不起作用，您需要在“Controller myController;”上进行获取/设置。它还需要公开(在某些情况下，它也适用于内部)。