转换器未挂接到 PropertyChanged 事件

Question

我有一个层次结构绑定到 entity framework 模型的树视图。下面的矩形仅适用于初始加载。并且在我触发 Propertychanged 事件时不会更新其颜色等。

<HierarchicalDataTemplate ItemsSource="{Binding tblLines}">
    <StackPanel Orientation="Horizontal" Margin="2">
        <Image Height="15" Margin="4" x:Name="imgTreeProject" Source="/DES STUDIO PR;component/Resources/Images/folder_closed.png"/>
        <TextBlock Text="{Binding Name}" Margin ="8" TextAlignment="Center" VerticalAlignment="Center" HorizontalAlignment="Center"/>
        <Rectangle Name="X" Width="10" Height="10" Fill="{Binding Path=.,Converter={StaticResource CheckoutConverter},UpdateSourceTrigger=PropertyChanged}" ToolTip="{Binding Path=.,Converter={StaticResource CheckoutPersonConverter},UpdateSourceTrigger=PropertyChanged}" ToolTipService.IsEnabled="{Binding Path=.,Converter={StaticResource CheckoutToolTipVis},UpdateSourceTrigger=PropertyChanged}"/>
    </StackPanel>

这是我的转换器：

public class CheckoutConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        if (value is TblBase)
        {
            var Baseentity = value as TblBase;

            if (Baseentity.COID == MainWindow.LocalUser.ID)
            {
                return Brushes.Green;
            }
            else if ((Baseentity.COID == 0) || (Baseentity.COID == null))
            {
                return Brushes.Transparent;
            }
            else if (Baseentity.COID != 0)
            {
                return Brushes.Black;
            }
        }
        return Brushes.Black;
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

public class CheckoutPersonConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        if (value is TblBase)
        {
            var Baseentity = value as TblBase;
            //COID equals other user's ID

            if ((Baseentity.COID != 0) && (Baseentity.COID != null) && (Baseentity.COID != MainWindow.LocalUser.ID))
            {
               var user = DESDatabase.GetUser(Baseentity.COID.Value);
               return "Checked out by " + user;
            }
            else if (Baseentity.COID == MainWindow.LocalUser.ID)
                return "You have this node checked out.";
            else
                return "error";
        }
        return "error";
    }

    public  object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

public class CheckoutToolTipVis : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        if (value is TblBase)
        {
            var Baseentity = value as TblBase;
            //COID equals other user's ID

            if ((Baseentity.COID != 0) && (Baseentity.COID != null))
            {
                return true;
            }
            else
                return false;
        }
        return true;
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

我的属性更改事件确实在此处调用：

private Nullable<int> _coid;
public Nullable<int> COID
{
    get
    {
        NotifyPropertyChanged();
        return _coid;
    }
    set
    {
        _coid = value;
        NotifyPropertyChanged();
    }
}

属性更改的事件适用于不使用转换器的 treeview 绑定，因此我不确定我缺少什么。

Answer 1

转换器 (IValueConverter) 不订阅 PropertyChanged 事件，这是绑定的责任。

当前转换器用于绑定到整个对象，而不是绑定到属性:

Fill="{Binding Path=.,Converter={StaticResource CheckoutConverter},UpdateSourceTrigger=PropertyChanged}"

所以 COID 的更新未被注意到。

您需要将出价更改为

Fill="{Binding Path=COID,Converter={StaticResource CheckoutConverter},UpdateSourceTrigger=PropertyChanged}"

并更改转换器：

public class CheckoutConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        if (value is int?)
        {
            var COID = value as int?;

            if (COID == MainWindow.LocalUser.ID)
            {
                return Brushes.Green;
            }
            else if ((COID == 0) || (COID == null))
            {
                return Brushes.Transparent;
            }
            else if (COID != 0)
            {
                return Brushes.Black;
            }
        }
        return Brushes.Black;
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

转换器未挂接到 PropertyChanged 事件

Converter not hooked to PropertyChanged event

c#

wpf

treeview

converter