CheckBox 绑定属性不会改变

Question

我有以下代码

Namespace WpfApplication1
{
    using System.ComponentModel;
    using System.Runtime.CompilerServices;

    using WpfApplication1.Annotations;
    using WpfApplication1.Enums;

    public class MainWindowViewModel : INotifyPropertyChanged
    {
        private bool _isItemEnabled;

        public MainWindowViewModel()
        {
            this.IsItemEnabled = false;
        }

        public event PropertyChangedEventHandler PropertyChanged;

        public bool IsItemEnabled
        {
            get
            {
                return this._isItemEnabled;
            }

            set
            {
                this._isItemEnabled = value;
                this.OnPropertyChanged(nameof(this.IsItemEnabled));
            }
        }


        [NotifyPropertyChangedInvocator]
        protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
        {
            this.PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}



<CheckBox Grid.Row="0" Grid.Column="1" Margin="0,20" 
          IsChecked="{Binding Path = TimeIsEnabled, Mode=OneWay, UpdateSourceTrigger=PropertyChanged }"
          DataContext="{Binding ElementName = MainWindowViewModel}">
    TestIsEnabled
</CheckBox>

当我单击复选框时，位于文件后面代码上的属性 TimeIsEnabled 不会更改，并且它的断点也不会触发。我试图在视图模型中找到这个属性，但结果是一样的。请帮忙。

Answer 1

尝试将模式从 OneWay 更改为 TwoWay (Mode=TwoWay)。如果您有OneWay 绑定，则属性会更新用户界面，但用户界面不会更新属性。

    <CheckBox Grid.Row="0" Grid.Column="1" Margin="0,20" 
              IsChecked="{Binding Path = TimeIsEnabled, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged }"
              DataContext="{Binding ElementName = MainWindowViewModel}">
        TestIsEnabled
    </CheckBox>

分析您发送的其余代码后，我发现了一些错误。首先，您绑定了错误的属性TimeIsEnabled 而不是IsItemEnabled。其次尝试像我在xaml 文件中那样构造DataContext下面：

<Window x:Class="WpfApplication3.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:WpfApplication3"
        mc:Ignorable="d"
        Title="MainWindow" Height="350" Width="525">
    <Window.DataContext>
        <local:MainWindowViewModel />
    </Window.DataContext>
    <Grid>
        <CheckBox Grid.Row="0" Grid.Column="1" Margin="0,20" 
          IsChecked="{Binding IsItemEnabled,Mode=TwoWay, UpdateSourceTrigger=PropertyChanged }">
            TestIsEnabled
        </CheckBox>
    </Grid>
</Window>

您的MainWindowViewModel 课程很好。我试过这个例子，它工作正常。