wpf checkbox IsChecked 绑定的正确方式

错误版

• xaml

<Window
    x:Class="checkboxtest.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:local="clr-namespace:checkboxtest"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    Title="MainWindow"
    Width="800"
    Height="450"
    mc:Ignorable="d">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto" />
        </Grid.RowDefinitions>
        <StackPanel Orientation="Vertical">
            <CheckBox Name="checkbox" Content="java" IsChecked="{Binding ChkChecked}" />
            <Button Click="Button_Click" Content="click" />
        </StackPanel>
    </Grid>
</Window>

• cs

using System.Windows;

namespace checkboxtest
{
    /// <summary>
    /// MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();

        }
        public bool? ChkChecked { get; set; }


        private void Button_Click(object sender, RoutedEventArgs e)
        {
            ChkChecked = !ChkChecked;
        }
    }
}

参考

https://oomake.com/question/2211787

正确版

using System.ComponentModel;
using System.Windows;

namespace checkboxtest
{
    /// <summary>
    /// MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow : Window, INotifyPropertyChanged
    {
        public MainWindow()
        {
            InitializeComponent();
            this.DataContext = this;

        }
        private bool? chkChecked = false;
        public bool? ChkChecked
        {
            get
            {
                return chkChecked;
            }
            set
            {
                chkChecked = value;
                RaisePropertyChanged("ChkChecked");
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;

        private void RaisePropertyChanged(string _Prop)
        {
            if (PropertyChanged != null)
            {
                this.PropertyChanged(this, new PropertyChangedEventArgs(_Prop));
            }
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            ChkChecked = !ChkChecked;
        }
    }
}

注意点

同时有字段和属性

必须同时有字段和属性, 否则启动报错

空指针错误

有时候会报如下空指针错误

代码修改为如下即可

        #region INotifyPropertyChanged
        public event PropertyChangedEventHandler PropertyChanged;
        private void RaisePropertyChanged(string prop)
        {
            if (null != prop && IsLoaded)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(prop));
            }
        }
        #endregion INotifyPropertyChanged