重写 ToString() 方法，使用 Binding 的行为很奇怪

Question

见下文XAML：

<Window x:Class="TabControl.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"        
    xmlns:local="clr-namespace:TabControl"
    Title="MainWindow"   Height="300" Width="300"        
    xmlns:Interact="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"       
    DataContext="{Binding RelativeSource={RelativeSource Mode=Self}}"       
    >   
<Window.Resources>
    <Style TargetType="{x:Type DataGridRow}" x:Key="myStyle">
        <Style.Triggers>
            <DataTrigger Binding="{Binding IsTrend.Value}" Value="True" >
                <Setter Property="Background" Value="Gold"/>
            </DataTrigger>
        </Style.Triggers>            
    </Style>
</Window.Resources>
<ScrollViewer>
    <DataGrid ItemsSource="{Binding list}" x:Name="myGrid" RowStyle="{StaticResource myStyle}"  >
        <DataGrid.Columns>
            <DataGridTextColumn Header="Name" Binding="{Binding Path=Name.Value,Mode=TwoWay}" />               
        </DataGrid.Columns>                       
    </DataGrid>
</ScrollViewer>

DataGrid来源

private ObservableCollection<dynamic> GetDynamicOrders2()
{
    var retVal = new ObservableCollection<dynamic>();
    for (int i = 0; i < 50; i++)
    {
        dynamic eo = new ExpandoObject();
        eo.Name = new CellContent("Order" + i);
        eo.IsTrend = new CellContent(i % 2 == 0);               
        retVal.Add(eo);
    }
    return retVal;
}

类

public sealed class CellContent : INotifyPropertyChanged
{
    private object _value;
    public object Value
    {
        get { return _value; }
        set
        {                
            _value = value;
            OnPropertyChanged("Value");               
        }
    }
    public CellContent(object value)
    {
        Value = value;            
    }             
    public event PropertyChangedEventHandler PropertyChanged;                
    private void OnPropertyChanged(string propertyName)
    {
        var handler = PropertyChanged;
        if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
    }
}

要从每个绑定中删除.Value，我override ToString()方法。

public override string ToString()
{
    return Value.ToString();
}

绑定更改为：

<DataGridTextColumn Header="Name" Binding="{Binding Path=Name,Mode=TwoWay}" />    

但它的行为对于DataTrigger和Column绑定是不同的。有人可以解释为什么以及如何吗？为什么DataTrigger在更改后不起作用？

Answer 1

<DataGridTextColumn Header="Name" Binding="{Binding Path=Name,Mode=TwoWay}" />  

DataGridTextColumn采用CellContent实例并调用ToString()来显示它。它显示Value，但不.Value路径，则不会应用数据网格单元格中的编辑。

<DataTrigger Binding="{Binding IsTrend}" Value="True" >

DataTrigger 采用CellContent实例并使用参数 "True" 调用 Equals()。但是 CellContent 对象不等于 "True" 。

如果我覆盖Equals，数据触发器工作

public override bool Equals(object obj)
{
    return Value.ToString() == (string) obj;
}