Question

我正在使用WPF应用。此应用使用OxyPlot chart control。我让用户进行计算。用户可以以网格和图表形式查看结果。为了做到这一点，我有以下内容：

home.xaml

<DataGrid x:Name="resultDataGrid" ItemsSource="{Binding Items}">
  <DataGrid.Columns>
    <DataGridTextColumn Header="#" Binding="{Binding Number}" />
    <DataGridTextColumn Header="Description" Binding="{Binding Description}" />
  </DataGrid.Columns>
</DataGrid>

<oxy:Plot x:Name="resultGraph" Background="Transparent" Height="400" HorizontalContentAlignment="Stretch" VerticalAlignment="Stretch" Visibility="Collapsed">
  <oxy:Plot.Series>
    <oxy:LineSeries ItemsSource="{Binding Points}" MarkerType="Circle"  Title="Result" />
  </oxy:Plot.Series>
</oxy:Plot>

<StackPanel Orientation="Horizontal">
  <Button x:Name="executeButton" Click="executeButton_Click" />
  <Button x:Name="viewData" Click="viewData_Click" />
  <Button x:Name="viewChart" Click="viewChart_Click" />
</StackPanel>

home.xaml.cs

public partial class Home: Page
{
  private MyViewModel viewModel = null;
  public Home()
  {
    InitializeComponent();

    viewModel = new MyViewModel();
    this.DataContext = viewModel;
  }

  private void executeButton_Click(object sender, RoutedEventArgs e) {
    viewModel.Execute();
  }

  private void viewData_Click(object sender, RoutedEventArgs e) 
  {
    resultDataGrid.Visibility = System.Windows.Visibility.Visible;
    resultGraph.Visibility = System.Windows.Visibility.Collapsed;
  }

  private void viewChart_Click(object sender, RoutedEventArgs e)
  {
    resultDataGrid.Visibility = System.Windows.Visibility.Collapsed;
    resultGraph.Visibility = System.Windows.Visibility.Visible;
  }
}

MyViewModel.cs

public class MyViewModel : INotifyPropertyChanged
{
  public Dictionary<int, string> Items{ get; set; }
  public IList<DataPoint> Points{ get; set; }

  public void Execute() 
  {
    this.Items = new Dictionary<int, string>();
    this.Points = new List<DataPoint>();

    var randomNumber = GetRandomNumber();
    for (var i=0; i<10; i++) 
    {
      this.Items.Add((i+1), "Item #" + i);

      var dataPoint = new DataPoint(i, (randomNumber*i));
      this.Points.Add(dataPoint);
    }

    NotifyPropertyChanged("Items");
    NotifyPropertyChanged("Points");
  }
}

我的问题是，当用户点击＆＃34;执行＆＃34;按钮，数据在DataGrid中刷新，这正是我所期待的。但是，如果图表首次可见，则只会刷新图表。换句话说，如果我点击＆＃34;执行＆＃34;当DataGrid可见时，图表中的绘图点变得陈旧。但是，如果我有resultGraph可见，我点击＆＃34;执行＆＃34;点数按预期刷新。我不明白我做错了什么。任何帮助表示赞赏。

Answer 1

在ViewModel中创建

private int _invalidateFlag = 0;
public int InvalidateFlag
{
   get {return _invalidateFlag;}
   set
   {
      _invalidateFlag = value;
      NotifyPropertyChanged();
   }
}

//and to the end of Execute() add

InvalidateFlag++;

也不要忘记绑定InvalidateFlag

<oxy:Plot x:Name="resultGraph" InvalidateFlag="{Binding InvalidateFlag}" Background="Transparent" Height="400" HorizontalContentAlignment="Stretch" VerticalAlignment="Stretch" Visibility="Collapsed">

这应该可以解决问题

Answer 2

其实我找到了答案here：

OxyPlot不会观察属性或集合更改。这意味着客户端应用程序负责在内容更改时刷新绘图。

更改后必须使绘图无效。有几个possibilities。

最简单的可能是 dirty MVVM：在视图中订阅viewmodel PropertyChanged事件，检查Points上升的此事件是否已更改并使绘图无效。

Answer 3

通常，OxyPlot提供方法PlotModel.InvalidatePlot(true)以使用新输入数据刷新图表。编辑：哦，我看到你的ViewModel中没有PlotModel属性。我的回答需要这样一个属性，它也可以绑定到xaml。

刷新OxyPlot图表

3 个答案: