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WPF 如何获取点的坐标（只想问关键的一部，获取此时选中的点） RRS feed

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  • 问题

  • Question
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    WPF 之前 画折线图，已经加入了datapoint ，有X，Y值；也同样加入了鼠标事件，现在就想知道怎样获取当前选中的点，以便后面编程。如下：

    private void dataPoint_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
            {
                    DataPoint dataPoint = （ 这里面怎么书写，能够获取此刻鼠标单击选中的点 ，急切 ）；                    
                    MessageBox.Show(dataPoint.YValue.ToString());
            }

    2014年4月2日 2:23
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答案

  • Question
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    你好，

    我不清楚你提到的DataPoint是什么，在WPF Chart 中，应该是LineDataPoint

    如果是按照我的方法创建的折线图的，可以为LineDataPoint指定 PreviewMouseLeftButtonDown 事件处理:

    XAML:

    xmlns:datavis="clr-namespace:System.Windows.Controls.DataVisualization;assembly=System.Windows.Controls.DataVisualization.Toolkit" 
        xmlns:charting="clr-namespace:System.Windows.Controls.DataVisualization.Charting;assembly=System.Windows.Controls.DataVisualization.Toolkit"
        Title="MainWindow" Height="350" Width="525">
    <Grid HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Margin="10" Grid.Column="1" Grid.Row="0">
        <charting:Chart x:Name="waitingtasks" BorderBrush="Transparent" BorderThickness="0" VerticalAlignment="Stretch" Title="Waiting Tasks">
            
            <charting:Chart.TitleStyle>
                <Style TargetType="datavis:Title">
                    <Setter Property="HorizontalAlignment" Value="Left"/>
                    <Setter Property="Foreground" Value="White"/>
                </Style>
            </charting:Chart.TitleStyle>
            <charting:Chart.LegendStyle>
                <Style TargetType="datavis:Legend">
                    <Setter Property="Width" Value="0" />
                </Style>
            </charting:Chart.LegendStyle>
            <charting:Chart.Axes>
                <charting:LinearAxis Orientation="X" Title="Time" Interval="20" ShowGridLines="False"/>
                <charting:LinearAxis Title="Number of Waiting Tasks" Orientation="Y" Interval="5" ShowGridLines="False"/>
            </charting:Chart.Axes>
            <charting:LineSeries DependentValuePath="Value" IndependentValuePath="Key" ItemsSource="{Binding}" IsSelectionEnabled="True" 
                                    AnimationSequence="FirstToLast" >
                <charting:LineSeries.DataPointStyle>
                    <Style TargetType="charting:LineDataPoint">
                        <EventSetter Event="Control.PreviewMouseLeftButtonDown" Handler="LineDataPoint_PreviewMouseLeftButtonDown"/>
                    </Style>
                </charting:LineSeries.DataPointStyle>
            </charting:LineSeries>
        </charting:Chart>
    </Grid>

    后台：

    ObservableCollection<KeyValuePair<double, double>> Power = new ObservableCollection<KeyValuePair<double, double>>();

public MainWindow()
{
            InitializeComponent();
            Power.Add(new KeyValuePair<double, double>(1, 0.4));
            Power.Add(new KeyValuePair<double, double>(2, 0.2));
            Power.Add(new KeyValuePair<double, double>(3, 0.5));
            Power.Add(new KeyValuePair<double, double>(4, 0.8));
            Power.Add(new KeyValuePair<double, double>(5, 0.1));
            Power.Add(new KeyValuePair<double, double>(6, 0.3));
            Power.Add(new KeyValuePair<double, double>(7, 0.7));
            waitingtasks.DataContext = Power;
}

private void LineDataPoint_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
            LineDataPoint dataPoint = (LineDataPoint)sender;
            MessageBox.Show("X: "+dataPoint.IndependentValue.ToString()+" Y: "+dataPoint.DependentValue.ToString());
}

    截图：


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    2014年4月3日 2:46
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    版主