Question

我必须为某些统计信息创建wpf应用程序。数据将来自数据库。现在，我尝试使用LiveCharts基本堆叠CartesianChart。我想在主窗口中有2个不同的图表。因此，我下载了一个示例，将其作为第一个图表，第二个作为副本。

但是，当我单击运行按钮以生成图表时（图表中的数据是一些随机值，以后它将来自LIST），我看到仅第一个图表为空。

这里xaml：

<ScrollViewer x:Name="ScrollViewerDay"
              VerticalScrollBarVisibility="Auto"
              HorizontalScrollBarVisibility="Hidden"
              Grid.Row="2"
              Grid.RowSpan="20"
              Grid.ColumnSpan="20">
    <StackPanel x:Name="StackDay"
                Grid.Column="0"
                Grid.Row="2"
                Grid.ColumnSpan="20"
                Grid.RowSpan="21"
                Margin="10,5,10,10">
        <Label x:Name="LabelDayTitle1"
               Content="Scrap Top10 (sorted by A2C number)"
               HorizontalAlignment="Center"
               HorizontalContentAlignment="Center"/>
        <lvc:CartesianChart x:Name="ChartDayA2C"
                            Series="{Binding SeriesCollectionDayA2C}"
                            LegendLocation="Bottom" MinHeight="280">
            <lvc:CartesianChart.AxisX>
                <lvc:Axis Title="Component scrap (Top10 A2C numbers) "
                          Labels="{Binding LabelsDayA2C}"
                          Separator="{x:Static lvc:DefaultAxes.CleanSeparator}" />
            </lvc:CartesianChart.AxisX>
            <lvc:CartesianChart.AxisY>
                <lvc:Axis Title="Usage"
                          LabelFormatter="{Binding FormatterDayA2C}">
                </lvc:Axis>
            </lvc:CartesianChart.AxisY>
        </lvc:CartesianChart>
        <Label x:Name="LabelDayTitle2"
               Content="Scrap Top10 (sorted by shape) "
               HorizontalContentAlignment="Center"
               HorizontalAlignment="Center"/>
        <lvc:CartesianChart x:Name="ChartDayShape"
                            Series="{Binding SeriesCollectionDayShape}"
                            LegendLocation="Bottom"
                            MinHeight="280">
            <lvc:CartesianChart.AxisX>
                <lvc:Axis Title="Component scrap (Top10 Shapes)"
                          Labels="{Binding LabelsDayShape}"
                          Separator="{x:Static lvc:DefaultAxes.CleanSeparator}" />
            </lvc:CartesianChart.AxisX>
            <lvc:CartesianChart.AxisY>
                <lvc:Axis Title="Usage"
                          LabelFormatter="{Binding FormatterDayShape}">
                </lvc:Axis>
            </lvc:CartesianChart.AxisY>
        </lvc:CartesianChart>
    </StackPanel>
</ScrollViewer>

以及此处的代码：

private void BtDailyShow_Click(object sender, RoutedEventArgs e)
{
    SeriesCollectionDayA2C = new SeriesCollection
    {
        new StackedColumnSeries
        {
            Values = new ChartValues<double> {4, 5, 6, 8},
            StackMode = StackMode.Values, // this is not necessary, values is the default stack mode
            DataLabels = true
        },
        new StackedColumnSeries
        {
            Values = new ChartValues<double> {200, 5, 6, 7},
            StackMode = StackMode.Values,
            DataLabels = true
        }
    };

    //adding series updates and animates the chart
    SeriesCollectionDayA2C.Add(new StackedColumnSeries
    {
        Values = new ChartValues<double> { 6, 2, 7 },
        StackMode = StackMode.Values
    });

    //adding values also updates and animates
    SeriesCollectionDayA2C[2].Values.Add(4d);

    LabelsDayA2C = new[] { "Chrome", "Mozilla", "Opera", "IE" };
    FormatterDayA2C = value => value + " Mill";

    DataContext = this;

    SeriesCollectionDayShape = new SeriesCollection
    {
        new StackedColumnSeries
        {
            Values=new ChartValues<double> {20,40,60,80 },
            StackMode=StackMode.Values,
            DataLabels =true
        },
        new StackedColumnSeries
        {
            Values = new ChartValues<double> {100,200,300,400 },
            StackMode=StackMode.Values,
            DataLabels=true
        }
    };
    SeriesCollectionDayShape.Add(new StackedColumnSeries
    {
        Values = new ChartValues<double> { 30, 50, 60, 90 },
        StackMode = StackMode.Values
    });
    SeriesCollectionDayShape[2].Values.Add(4d);
    LabelsDayShape = new[] { "aaaa", "aass", "eeee", "laka" };
    FormmatterDayShape= value => value + " Mill";
    DataContext = this;
}

public SeriesCollection SeriesCollectionDayShape { get; set; }
public SeriesCollection SeriesCollectionDayA2C { get; set; }
public string[] LabelsDayA2C { get; set; }
public string[] LabelsDayShape { get; set; }
public Func<double, string> FormatterDayA2C { get; set; }
public Func<double,string> FormatterDayShape { get; set; }
public Func<object, object> FormmatterDayShape { get; set; }

有人可以帮助我哪里出错了吗？

Answer 1

错误是第一行与

DataContext = this;

如果将其删除，它应该可以工作。在构造函数的末尾设置一次DataContext。

为什么？

wpf中的

绑定是 smart ，它们能够监视属性的变化。为此，您必须为每种类型实现INotifyPropertyChanged，并使用属性名称引发PropertyChanged事件，该事件的属性值已更改。您可以通过说完所有内容使代码正常工作。

对于永不更改的属性，不需要通知，但这意味着您必须在所有这些属性都设置了其值之后DataContext 之后进行设置。

WPF有很多优化，因此通常在属性设置器中有一个check if value is a new，这会引起很多问题，包括您的情况。解决您问题的另一种可能性是以方式执行 refresh 的价值：

DataContext = this; // first time
...

DataContext = null;
DataContext = this; // refresh the value

WPF实时图表

1 个答案: