Question

我正在努力绑定到依赖属性。

我的应用程序有一个MainWindow。这是一个usercontrol（称为时间轴）。在TimeLine UserControl中是另一个名为MoveMe的Control。

我可以从MainWindow绑定到时间轴UserControl的依赖项属性。当我使用OneWayToSource绑定时，我可以从MoveMe绑定到MoveMe UserControl。但是，我正在尝试从时间轴UserControl绑定到MoveMe控件（从父级到子级）。但是，绑定不起作用。我把一只手表放在MoveMe财产的制定者身上，它从未被解雇过。

“输出”窗口中没有绑定问题。

我的MainWindow.xaml已

<timeline:TimeLine StartTime="{Binding StartTime}" 
                                       EndTime="{Binding EndTime}" 
                                       TestEvents="{Binding TestEvents}" 
                                       CampaignDetails="{Binding CampaignDetails}" 
                                       ShowReportPeriod="True" HorizontalAlignment="Stretch"/>

我的时间线.xaml

<userControls:MoveMe 
        StartMarkerPositionPixels="{Binding RelativeSource={RelativeSource AncestorType=userControls:TimeLine}, Path=StartMarkerPosition, Mode=OneWayToSource}"               
        EndReportPositionInPixels="{Binding RelativeSource={RelativeSource AncestorType=userControls:TimeLine}, Path=EndOfReportPosition, Mode=OneWay}" 
        x:Name="ReportSelectorStart" />

并且它的DataContext设置为

<UserControl DataContext="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorLevel=1,AncestorType=Window}}"...

因此，正如您在上面所见，在timeline.xaml中有2个属性被绑定，第一个是StartMarkerPositionPixels，它是OneWayToSource。这很好用。问题是第二个，EndReportPositionInPixels，因为它没有绑定。

MoveMe控件背后的代码

using System.ComponentModel;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Controls.Primitives;

namespace TimeLineCanvas.UserControls
{
    /// <summary>
    /// Interaction logic for MoveMe.xaml
    /// </summary>
    public partial class MoveMe : UserControl
    {
        public MoveMe()
        {
            InitializeComponent();            
            //this.DataContext = this;
        }

        public double StartMarkerPositionPixels
        {
            get { return (double)GetValue(StartMarkerPositionProperty); }
            set { SetValue(StartMarkerPositionProperty, value); }
        }

        public double EndReportPositionInPixels
        {
            get { return (double)GetValue(ScaleFactorProperty); }
            set { SetValue(ScaleFactorProperty, value);
            OnPropertyChanged("EndReportPositionInPixels");
            }
        }

        public static readonly DependencyProperty EndMarkerPositionProperty = DependencyProperty.Register(
            "EndMarkerPositionPixels",
            typeof(double),
            typeof(MoveMe));

        public static readonly DependencyProperty EndReportPositionInPixelsPoperty = DependencyProperty.Register(
          "EndReportPositionInPixels",
          typeof(double),
          typeof(MoveMe));

    }
}

在我的TimeLine代码隐藏中，我有以下

    private double _endOfReportPosition;
    public double EndOfReportPosition
    {
        get { return _endOfReportPosition; }
        set
        {
            _endOfReportPosition = value;
            //this.ReportSelectorStart.EndMarkerPositionPixels = value;//If I hardcode it in, then it works, but I want it bind
            OnPropertyChanged("EndOfReportPosition");
        }
    }

输出窗口确认没有绑定错误。

我的问题是，如何通过依赖项属性将TimeLine控件中的值传递给我的MoveMe控件。

Answer 1

首先，您不需要INPC用于依赖项属性。再看看这段代码 -

    public double EndReportPositionInPixels
    {
        get { return (double)GetValue(ScaleFactorProperty); }
        set { SetValue(ScaleFactorProperty, value); }
    }

您在此处设置并获取ScaleFactorProperty的值。不应该EndReportPositionInPixelsPoperty这样 -

    public double EndReportPositionInPixels
    {
        get { return (double)GetValue(EndReportPositionInPixelsPoperty); }
        set { SetValue(EndReportPositionInPixelsPoperty, value); }
    }

无法绑定到依赖项属性

1 个答案: