wpf - 更改绑定(bind)属性的值时如何为文本 block 的背景设置动画？

Question

我有一个非常简单的 wpftoolkit:da​​tagrid 来显示股票市场的买入和卖出。

我的网格绑定(bind)到 ObservableCollection<PriceViewModel> .我的 PriceViewModel实现 INotifyPropertyChanged .

网格正确更新，我已经设法让背景颜色进行动画处理，但在应用动画时它是断断续续的。

下面是 View 模型类的 XAML 和片段。

这个想法只是在价格更新低于以前的价格时将其涂成红色，而在价格更新时将其涂成绿色......没什么太花哨的。

     <WpfToolkit:DataGrid Name="PriceDataGrid" RowHeaderWidth="5" 
AutoGenerateColumns="False" VerticalContentAlignment="Center" Margin="0,33,0,0" HorizontalAlignment="Left" Width="868">
        <WpfToolkit:DataGrid.Columns>
            <WpfToolkit:DataGridTemplateColumn Header="Bid"  MinWidth="40">
                <WpfToolkit:DataGridTemplateColumn.CellTemplate>
                    <DataTemplate>
                        <TextBlock Text="{Binding Bid}" Margin="3,1" x:Name="txtTextBlock">
                            <TextBlock.Background>
                                <SolidColorBrush Color="Transparent"></SolidColorBrush>
                            </TextBlock.Background>
                        </TextBlock>
                        <DataTemplate.Triggers>
                            <DataTrigger Binding="{Binding BidUp}" Value="True">
                                <DataTrigger.EnterActions>
                                    <BeginStoryboard>
                                        <Storyboard>
                                            <ColorAnimation 
                                                BeginTime="00:00:00"
                                                Duration="0:0:0.1" 
                                                To="Green" 
                                                AutoReverse="True"
                                                Storyboard.TargetName="txtTextBlock" 
                                                Storyboard.TargetProperty="(TextBlock.Background).(SolidColorBrush.Color)">
                                            </ColorAnimation>
                                        </Storyboard>
                                    </BeginStoryboard>
                                </DataTrigger.EnterActions>
                            </DataTrigger>
                            <DataTrigger Binding="{Binding BidDown}" Value="True">
                                <DataTrigger.EnterActions>
                                    <BeginStoryboard>
                                        <Storyboard>
                                            <ColorAnimation 
                                                BeginTime="00:00:00"
                                                Duration="0:0:0.1" 
                                                To="Red" 
                                                AutoReverse="True"
                                                Storyboard.TargetName="txtTextBlock" 
                                                Storyboard.TargetProperty="(TextBlock.Background).(SolidColorBrush.Color)">
                                            </ColorAnimation>
                                        </Storyboard>
                                    </BeginStoryboard>
                                </DataTrigger.EnterActions>
                            </DataTrigger>
                        </DataTemplate.Triggers>
                    </DataTemplate>
                </WpfToolkit:DataGridTemplateColumn.CellTemplate>
            </WpfToolkit:DataGridTemplateColumn>
            <WpfToolkit:DataGridTextColumn Header="Ask" Binding="{Binding Path=Ask}" MinWidth="40" />
        </WpfToolkit:DataGrid.Columns>
    </WpfToolkit:DataGrid>

和 View 模型:

public class PriceViewModel : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;

    Price _price;

    private bool _bidUp = false;
    private bool _bidDown = false;


    public bool BidUp
    {
        get
        {
            return _bidUp;
        }

        set
        {
            _bidUp = value;
            OnPropertyChanged("BidUp");
        }
    }
    public bool BidDown
    {
        get
        {
            return _bidDown;
        }

        set
        {
            _bidDown = value;
            OnPropertyChanged("BidDown");
        }
    }

    public double Bid 
    { 
        get { return _price.Bid; }
        set
        {
            BidUp = (value > _price.Bid);
            BidDown = (value < _price.Bid);

            _price.Bid = value; 
            OnPropertyChanged("Bid");
        } 
    }

    public double Ask 
    { 
        get { return _price.Ask; } 
        set 
        {
            AskUp = (value > _price.Ask);
            _price.Ask = value; 
            OnPropertyChanged("Ask"); 
        } 
    }


    public PriceViewModel(Price price)
    {
        _price = price;
    }

    private void OnPropertyChanged(string propertyName)
    {
        if(PropertyChanged != null)
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
    }

}

Answer 1

我试过了，如果你停止 Storyboard 似乎效果会更好在你开始新的之前。停止 Storyboard ，命名并调用

<StopStoryboard BeginStoryboardName="bidUpStoryboard"/>

像这样试试

<DataTemplate.Triggers>
    <DataTrigger Binding="{Binding BidUp}" Value="True">
        <DataTrigger.EnterActions>
            <StopStoryboard BeginStoryboardName="bidUpStoryboard"/>
            <StopStoryboard BeginStoryboardName="bidDownStoryboard"/>
            <BeginStoryboard Name="bidUpStoryboard">
                <Storyboard BeginTime="00:00:00">
                    <ColorAnimation 
                        BeginTime="00:00:00"
                        Duration="0:0:0.1" 
                        To="Green" 
                        AutoReverse="True"
                        Storyboard.TargetName="txtTextBlock" 
                        Storyboard.TargetProperty="(TextBlock.Background).(SolidColorBrush.Color)">
                    </ColorAnimation>
                </Storyboard>
            </BeginStoryboard>
        </DataTrigger.EnterActions>
    </DataTrigger>
    <DataTrigger Binding="{Binding BidDown}" Value="True">
        <DataTrigger.EnterActions>
            <StopStoryboard BeginStoryboardName="bidUpStoryboard"/>
            <StopStoryboard BeginStoryboardName="bidDownStoryboard"/>
            <BeginStoryboard Name="bidDownStoryboard">
                <Storyboard BeginTime="00:00:00">
                    <ColorAnimation 
                        BeginTime="00:00:00"
                        Duration="0:0:0.1" 
                        To="Red" 
                        AutoReverse="True"
                        Storyboard.TargetName="txtTextBlock" 
                        Storyboard.TargetProperty="(TextBlock.Background).(SolidColorBrush.Color)">
                    </ColorAnimation>
                </Storyboard>
            </BeginStoryboard>
        </DataTrigger.EnterActions>
    </DataTrigger>
</DataTemplate.Triggers>

此外，如果 BidUp连续两次设置为true，它不会触发第二次，因为它会从true变为true，因此如果您希望每次值更改时都出现闪烁效果，您必须将其设置为false一点。例如

public double Bid
{
    get { return _price.Bid; }
    set
    {
        BidUp = false;
        BidDown = false;
        BidUp = (value > _price.Bid);
        BidDown = (value < _price.Bid);
        _price.Bid = value;
        OnPropertyChanged("Bid"); }
}