具有依赖属性的 WPF 绑定。数据不显示的问题

Question

我整个上午都在尝试让它工作，但没有运气。我正在使用 DynamicDataDisplay (D3) 来显示图表。这是我使用 xaml 定义的简单视图。

<Window x:Class="BMSVM_Simulator.View.GraphWindowView"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:ViewModel="clr-namespace:BMSVM_Simulator.ViewModel"
        xmlns:d3="http://research.microsoft.com/DynamicDataDisplay/1.0"
        x:Name="ThisGraphWindowInstance"
        Title="Plot" Height="500" Width="750"
        WindowStartupLocation="CenterOwner"
        Icon="../res/qualcomm_q_icon.ico.ico"
        MinWidth="400" MinHeight="300">

    <Window.DataContext>
        <ViewModel:GraphWindowPresenter/>
    </Window.DataContext>

    <Grid>
        <d3:ChartPlotter Name="plotter" Margin="10,10,20,10">
            <d3:InjectedPlotter Name="innerPlotter" Background="Aqua" SetViewportBinding="False">
                <d3:VerticalAxis Placement="Right"/>
                <d3:VerticalAxisTitle Content="{Binding ElementName=ThisGraphWindowInstance, Path=yAxis2}" Placement="Right"/>
            </d3:InjectedPlotter>      

            <d3:Header FontFamily="Arial" Content="{Binding ElementName=ThisGraphWindowInstance, Path=title}"/>
            <d3:VerticalAxisTitle FontFamily="Arial" Content="{Binding ElementName=ThisGraphWindowInstance, Path=yAxis2}"/>
            <d3:HorizontalAxisTitle FontFamily="Arial" Content="{Binding ElementName=ThisGraphWindowInstance, Path=title}"/>
        </d3:ChartPlotter>
    </Grid>
</Window>

问题在于：

<d3:VerticalAxisTitle Content="{Binding ElementName=ThisGraphWindowInstance, Path=yAxis2}" Placement="Right"/>

当我使用当前设置并将Content 绑定到Path=yAxis2 时，InjectedPlotter 中根本不显示。我在断点处设置，我看到yAxis2 实际上是一个已定义的字符串并且它不为空。

当我实际硬编码一个值，例如Content="DEFAULT TITLE"，那么它就变成了：

<d3:VerticalAxisTitle Content="DEFAULT TITLE" Placement="Right"/>

标题显示正常。

有人知道为什么会这样吗？

后面的代码供参考：

public static readonly DependencyProperty yAxis2Property =
    DependencyProperty.Register("yAxis2", typeof(string), typeof(GraphWindowView));

public string yAxis2
{
    get { return (string)GetValue(yAxis2Property); }
    set { SetValue(yAxis2Property, value); }
}

public void ShowGraph()
{
    // consume ChartData
    this.yAxis1 = ChartData.yAxisTitle1;
    this.yAxis2 = "AXIS 2 TITLE..SHOW UP!";
     .....
}

编辑>>>>>>>>>

using BMSVM_Simulator.ViewModel;
using Microsoft.Research.DynamicDataDisplay;
using Microsoft.Research.DynamicDataDisplay.DataSources;
using Microsoft.Research.DynamicDataDisplay.Navigation;
using Microsoft.Research.DynamicDataDisplay.PointMarkers;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;

namespace BMSVM_Simulator.View
{
    /// <summary>
    /// Interaction logic for Window1.xaml
    /// </summary>
    public partial class GraphWindowView : Window
    {
        #region Fields

        private readonly int DEFAULT_AXIS_WIDTH = 20;

        private readonly Pen[] colors = {   
                                            new Pen(Brushes.Blue, 2),
                                            new Pen(Brushes.DarkGreen, 2),
                                            new Pen(Brushes.DarkMagenta, 2),
                                            new Pen(Brushes.DarkSalmon, 2),
                                            new Pen(Brushes.Maroon, 2),
                                            new Pen(Brushes.Orange, 2),
                                            new Pen(Brushes.SkyBlue, 2)
                                        };

        #endregion

        #region DependencyProperties

        public static readonly DependencyProperty yAxis1Property =
            DependencyProperty.Register("yAxis1", typeof(string), typeof(GraphWindowView));

        public static readonly DependencyProperty yAxis2Property =
            DependencyProperty.Register("yAxis2", typeof(string), typeof(GraphWindowView));

        public static readonly DependencyProperty titleProperty =
            DependencyProperty.Register("title", typeof(string), typeof(GraphWindowView));

        public static readonly DependencyProperty xAxisProperty =
            DependencyProperty.Register("xAxis", typeof(string), typeof(GraphWindowView));

        public static readonly DependencyProperty DatesProperty =
            DependencyProperty.Register("Dates", typeof(EnumerableDataSource<int>), typeof(GraphWindowView));

        public static readonly DependencyProperty DataProperty =
            DependencyProperty.Register("Data", typeof(EnumerableDataSource<int>), typeof(GraphWindowView));

        public static readonly DependencyProperty ChartDataProperty =
            DependencyProperty.Register("ChartData", typeof(ChartData), typeof(GraphWindowView));

        public static readonly DependencyProperty rightAxisWidthProperty =
            DependencyProperty.Register("rightAxisWidth", typeof(int), typeof(GraphWindowView));

        public int rightAxisWidth
        {
            get { return (int)GetValue(rightAxisWidthProperty); }
            set { SetValue(rightAxisWidthProperty, value); }
        }

        public ChartData ChartData
        {
            get { return (ChartData)GetValue(ChartDataProperty); }
            set { SetValue(ChartDataProperty, value); }
        }

        public EnumerableDataSource<int> Dates
        {
            get { return (EnumerableDataSource<int>)GetValue(DatesProperty); }
            set { SetValue(DatesProperty, value); }
        }

        public EnumerableDataSource<int> Data
        {
            get { return (EnumerableDataSource<int>)GetValue(DataProperty); }
            set { SetValue(DataProperty, value); }
        }

        public string xAxis
        {
            get { return (string)GetValue(xAxisProperty); }
            set { SetValue(xAxisProperty, value); }
        }

        public string yAxis1
        {
            get { return (string)GetValue(yAxis1Property); }
            set { SetValue(yAxis1Property, value); }
        }

        public string title
        {
            get { return (string)GetValue(titleProperty); }
            set { SetValue(titleProperty, value); }
        }

        public string yAxis2
        {
            get { return (string)GetValue(yAxis2Property); }
            set { SetValue(yAxis2Property, value); }
        }

        #endregion

        public GraphWindowView()
        {
            InitializeComponent();
            rightAxisWidth = DEFAULT_AXIS_WIDTH;
        }

        public void ShowGraph()
        {
            // consume ChartData
            this.xAxis = ChartData.xAxisTitle;
            this.yAxis1 = ChartData.yAxisTitle1;
            this.yAxis2 = "AXIS 2 TITLE..SHOW UP!"; // ChartData.yAxisTitle2;
            this.title = ChartData.title;
            this.rightAxisWidth = DEFAULT_AXIS_WIDTH;

            // list of data points
            List<DataSet> dataSets = this.ChartData.dataPoints;

            int colorCounter = 0;
            int rightAxisCount = 0;
            foreach (DataSet set in dataSets)
            {

                set.dates.SetXMapping(x => x);
                set.data.SetYMapping(x => x);

                CompositeDataSource compositeDataSource1 = new
                    CompositeDataSource(set.dates, set.data);

                if (set.axis == AxisSide.LEFT)
                {
                    plotter.AddLineGraph(compositeDataSource1, colors[colorCounter % colors.Length],
                    new CirclePointMarker { Size = 8.00, Fill = Brushes.Red },
                    new PenDescription(set.legendTitle));
                }
                else
                {
                    innerPlotter.AddLineGraph(compositeDataSource1, colors[colorCounter % colors.Length],
                    new CirclePointMarker { Size = 8.00, Fill = Brushes.Red },
                    new PenDescription(set.legendTitle));

                    rightAxisCount++;
                }


                colorCounter++;
            }

            // if there is nothing plotted against the right axis, don't show it
            if (rightAxisCount == 0)
            {
                rightAxisWidth = 0;
            }

            plotter.Viewport.FitToView();

            // there are duplicate legends, so we hide one
            plotter.LegendVisibility = Visibility.Hidden;

            Show();
        }
    }
}

Answer 1

在您提供的代码中，您已将 datacontext 设置为 GraphWindowPresenter 的对象，但在声明依赖属性时您已设置 GraphWindowView 对象。请确保将适当的对象设置为 datacontext

    <Window.DataContext>
       < ViewModel:GraphWindowPresenter/>
  < /Window.DataContext>

DependencyProperty.Register("yAxis2", typeof(string), typeof(GraphWindowView))

Answer 2

试试：

      <d3:VerticalAxisTitle Content="{Binding RelativeSource={RelativeSource AncestorType=Window}, Path=yAxis2,Mode=OneWay}" />

Answer 3

我运行了一个绑定TextBox.Text 的快速测试，并且您发布的代码有效。

<Window x:Class="WpfApplication2.MainWindow"
        x:Name="TestWindow" ...>
    <StackPanel>
        <!-- both bindings work -->
        <TextBlock Text="{Binding ElementName=TestWindow, Path=yAxis2}" />
        <TextBlock Text="{Binding RelativeSource={RelativeSource AncestorType={x:Type local:MainWindow}}, Path=yAxis2}" />
    </StackPanel>
</Window>

public partial class MainWindow : Window
{
    public static readonly DependencyProperty yAxis2Property =
        DependencyProperty.Register("yAxis2", typeof(string), typeof(MainWindow));

    public string yAxis2
    {
        get { return (string)GetValue(yAxis2Property); }
        set { SetValue(yAxis2Property, value); }
    }

    public MainWindow()
    {
        InitializeComponent();
        this.yAxis2 = "TESTING";
    }

}

所以我最好的猜测是

• 你没有在窗口上调用ShowGraph()
• 或 VerticalAxisTitle 对象不是 Visual Tree 中存在的对象，与 DataGridColumn 等其他一些 WPF 对象非常相似

要确定第一个问题是否是您的问题，只需确保您在窗口后面的构造函数中调用ShowGraph()，或者只需按照我在此处进行测试的方式设置yAxis2。

您还可以使用像 Snoop 这样的工具，它对于调试运行时数据绑定非常有用。

如果完成后仍然无法正确显示，那么您可能需要对VerticalAxisTitle 进行更多研究，以找到如何正确绑定它的解决方法。如果您无法找到特定于 VerticalAxisTitle 的任何内容，请尝试查找 DataGridColumn 的具体情况，例如 this answer。

（附带说明一下，将公共属性大写是一个标准约定，因此您的属性应该是YAxis2。只是我的强迫症开始了。）:)