Question

我正在开发某种时间跟踪应用程序。

该模型如下所示：

我的DataGrid绑定到ObservableCollection<Entry>：

public class Entry : INotifyPropertyChanged
{
    public string TicketId {get; set;} //Simplified since working..

    private ObservableCollection<TimeBooking> _timebookings;
    public ObservableCollection<TimeBooking> TimeBookings
    {  
        get { return _timebookings; }
        set
        {
            _timebookings = value;
            OnPropertyChanged();
        }
    }

    public TimeBooking Monday //Same for other days...
    {
        get
        {
            return Bookings.Where(b => b.Date == SelectedWeek.FirstDay);
        }
    } 
}

TimeBooking看起来像这样：

public class TimeBooking : INotifyPropertyChanged
{
    public TimeBooking(DateTime date)
    {
        Date = date.Date;           
    }

    public DateTime Date { get; set; }

    private TimeSpan _value;
    public TimeSpan Value
    {        
        get
        {
            return _value;
        }
        set
        {
            _value = value;
            OnPropertyChanged();
        }
    }

    private bool _changed;
    public bool Changed         //CHANGED SETTER IS INVOKED BY CELL CONTEXT MENU
    {
        get { return _changed; }
        set
        {
            _changed = value;
            OnPropertyChanged();
        }
    }


    #region Implementation of INotifyPropertyChanged

    public event PropertyChangedEventHandler PropertyChanged;

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

    #endregion Implementation of INotifyPropertyChanged

}

问题在这里：

 <DataGrid.CellStyle>
     <Style TargetType="DataGridCell">
        <Style.Triggers>
            <DataTrigger Binding="{Binding RelativeSource={RelativeSource Self}, Converter={StaticResource EditedConverter}, UpdateSourceTrigger=Explicit}" Value="True">
                <Setter Property="Foreground" Value="Pink" />
            </DataTrigger>
            <DataTrigger Binding="{Binding RelativeSource={RelativeSource Self}, Converter={StaticResource EditedConverter}, UpdateSourceTrigger=Explicit}" Value="False">
                 <Setter Property="Foreground" Value="Lime" />
             </DataTrigger>
         </Style.Triggers>
         <Setter Property="ContextMenu" Value="{StaticResource CellContextMenu}" />
     </Style>
 </DataGrid.CellStyle>

这是我的转换器：

public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        DataGridCell dgc = value as DataGridCell;
        if(dgc != null)
        {
            ENTRY entry = dgc.DataContext as _ENTRY;
            if(entry != null)
            {
                DataGridTextColumn column = dgc.Column as DataGridTextColumn;
                if(column != null)
                {
                    var binding = column.Binding as Binding;
                    if(binding != null && binding.Path != null && binding.Path.Path != null)
                    {
                        string val = binding.Path.Path.ToLower();
                        if (val.StartsWith("monday"))
                        {
                            return entry.monday.Changed;
                        }
                        if (val.StartsWith("tuesday"))
                        {
                            return entry.tuesday.Changed;
                        }
                        if (val.StartsWith("wednesday"))
                        {
                            return entry.wednesday.Changed;
                        }
                        if (val.StartsWith("thursday"))
                        {
                            return entry.thursday.Changed;
                        }
                        if (val.StartsWith("friday"))
                        {
                            return entry.friday.Changed;
                        }
                        if (val.StartsWith("saturday"))
                        {
                            return entry.saturday.Changed;
                        }
                        if (val.StartsWith("sunday"))
                        {
                            return entry.sunday.Changed;
                        }
                    }
                }
            }
        }
        return false;
    }

正如我们所看到Binding到Changed正在运行（Foreground是Lime），但不会注意到该属性的某些变化..

Answer 1

如果您希望在filters: [myFilter]属性设置为新值时调用转换器，则可以使用aa Changed和多转换器（实现MultiBinding）：

IMultiValueConverter

<Style TargetType="DataGridCell">
    <Setter Property="Foreground" Value="Pink" />
    <Style.Triggers>
        <DataTrigger Value="false">
            <DataTrigger.Binding>
                <MultiBinding Converter="{StaticResource multiConverter}">
                    <Binding Path="Changed" />
                    <Binding Path="." RelativeSource="{RelativeSource Self}" />
                </MultiBinding>
            </DataTrigger.Binding>
            <Setter Property="Foreground" Value="Lime" />
        </DataTrigger>
    </Style.Triggers>
    <Setter Property="ContextMenu" Value="{StaticResource CellContextMenu}" />
</Style>

}

Answer 2

在看到转换器之后，我可以告诉你，你没有在数据更改时触发转换器的原因是因为你绑定到Control，当你从其中一个改变一个值时，它不会改变你属性。

为了能够实现你想要的，你必须在你的datacontext viewmodel中做一个累积属性，并将触发器绑定到那个或其他方式。

Answer 3

试试这个

   public ObservableCollection<TimeBooking> TimeBookings
{  
    get { return _timebookings; }
    set
    {
        _timebookings = value;
        OnPropertyChanged("TimeBookings");
    }
}

等等。

在调用PropertyChanged后绑定不更新

3 个答案: