Question

我在Usercontrol（InfoControl）中有2个TextBox，它们绑定到实现INotifyPropertyChanged的VM中的Point属性。

我有另一个UserControl（DesignerControl），它包含一个可拖动的矩形。 Rectangle的Canvas.Left和Canvas.Bottom绑定到同一VM的ConvPoint属性。 ConvPoint Property（0 =＆gt; ActualWidth）是Point Property的转换版本（0 =＆gt; 1）

当我拖动我的矩形时，ConvPoint VM属性和文本框中的值会立即更新，但是当我使用新值更新文本框时，VM Point属性会立即更新，但只有当我拖动时才会定位矩形矩形，而不是立即。

一些代码来解释：

首先，我的ViewModel的位置属性

public class MyVM : ViewModelBase
{
    private DependencyPoint position;
    public DependencyPoint Position
    {
        get { return this.position; }
        set
        {
            this.position = value;
            RaisePropertyChanged("Position");
        }
    }

    public DependencyPoint ConvPosition
    {
        get { return new Point(this.Position.X * MainVM.ActualWidth, this.Position.Y * MainVM.AcutalHeight);}
        set
        {
            Point p = new Point(value.X/MainVM.ActualWidth,value.Y/MainVM.ActualHeight);
            this.position = p;
            RaisePropertyChanged("ConvPosition");
        }
    }
}

修改我正在使用这个类DependencyPoint来通知X和Y属性：

public class DependencyPoint : DependencyObject
{

    public enum PointOrder
    {
        isStartPoint,
        isEndPoint,
        isPoint1,
        isPoint2
    }

    public DependencyPoint()
    {
    }

    public DependencyPoint(Double x, Double y, PointOrder po)
    {
        this.X = x;
        this.Y = y;
        this.Order = po;
    }

    public DependencyPoint(DependencyPoint point)
    {
        this.X = point.X;
        this.Y = point.Y;
        this.Order = point.Order;
    }


    public DependencyPoint(Point point, PointOrder po)
    {
        this.X = point.X;
        this.Y = point.Y;
        this.Order = po;
    }

    public Point ToPoint()
    {
        return new Point(this.X, this.Y);
    }



    public PointOrder Order
    {
        get { return (PointOrder)GetValue(OrderProperty); }
        set { SetValue(OrderProperty, value); }
    }

    // Using a DependencyProperty as the backing store for Order.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty OrderProperty =
        DependencyProperty.Register("Order", typeof(PointOrder), typeof(DependencyPoint), new UIPropertyMetadata(null));



    public Double X
    {
        get { return (Double)GetValue(XProperty); }
        set { SetValue(XProperty, value); }
    }

    // Using a DependencyProperty as the backing store for X.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty XProperty =
        DependencyProperty.Register("X", typeof(Double), typeof(DependencyPoint), new UIPropertyMetadata((double)0.0));



    public Double Y
    {
        get { return (Double)GetValue(YProperty); }
        set { SetValue(YProperty, value); }
    }

    // Using a DependencyProperty as the backing store for Y.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty YProperty =
        DependencyProperty.Register("Y", typeof(Double), typeof(DependencyPoint), new UIPropertyMetadata((double)0.0));
}

然后在我的InfoControl中：

<Grid Grid.Row="0" DataContext="{Binding Position}">
                <Grid.RowDefinitions>
                    <RowDefinition/>
                    <RowDefinition/>
                </Grid.RowDefinitions>
                <DockPanel Margin="3,3,0,1" Grid.Row="0" LastChildFill="True">
                    <TextBlock Foreground="White" Padding="0,3,0,0" Margin="2,0,0,0" DockPanel.Dock="Left" Text="StartPoint.X :"/>
                    <TextBox FontWeight="DemiBold" Foreground="Black" Background="#efefef" Width="Auto" Margin="7,0,0,0" Text="{Binding X, Converter={StaticResource StDConverter}, UpdateSourceTrigger=LostFocus, Mode=TwoWay}"/>
                </DockPanel>
                <DockPanel Margin="3,3,0,1" Grid.Row="1" LastChildFill="True">
                    <TextBlock Foreground="White" Padding="0,3,0,0" Margin="2,0,0,0" DockPanel.Dock="Left" Text="StartPoint.Y :"/>
                    <TextBox FontWeight="DemiBold" Foreground="Black" Background="#efefef" Width="Auto" Margin="7,0,0,0" Text="{Binding Y, Converter={StaticResource StDConverter}, UpdateSourceTrigger=LostFocus, Mode=TwoWay}"/>
                </DockPanel>
            </Grid>

在DesignerControl中：

<UserControl>
    <Canvas>
        <Rectangle x:Name="Point" Width="10" Height="10" Canvas.Bottom="{Binding ConvPosition.Y, Mode=TwoWay}" Canvas.Left="{Binding ConvPosition.X, Mode=TwoWay}" />
    </Canvas>
</UserControl>

我可以访问actualWidth，并且我的Rectangle在Canvas中定位良好。

我知道我在VM中的属性或有点脏，但我不知道另一种方法来正确地执行它并管理转换。

任何想法？

Answer 1

因为ConvPosition取决于位置，你应该在位置设置器中为ConvPosition引发NotificationChanged。

public Point Position
{
    get { return this.position; }
    set
    {
        this.position = value;
        RaisePropertyChanged("Position");
        RaisePropertyChanged("ConvPosition");
    }
}

ConvPosition你可以改成这个

public Point ConvPosition
{
    get { return new Point(this.Position.X * MainVM.ActualWidth, this.Position.Y * MainVM.AcutalHeight); }
    set
    {
        this.Position = new Point(value.X/MainVM.ActualWidth, value.Y/MainVM.ActualHeight);
    }
}

修改

我认为MyVM中的另外两个属性是最简单的解决方案。

public double X { get { return Position.X; } set { Position = new Point(value, Position.Y); RaisePropertyChanged("X"); } } public double Y { get { return Position.Y; } set { Position = new Point(Position.X, value); RaisePropertyChanged("Y"); } }

仅更改网格：

<Grid DataContext="{Binding}">

wpf usercontrol定位在绑定的TextBox时不会立即更新

1 个答案: