我修改了scrollable example以使用Rachel Lim的VMMV navigation example并从我们的数据库中获取数据。我还将一些代码隐藏逻辑移到了VM上。使用LiveCharts.ChartValues可以正常工作，但在使用LiveCharts.Geared.GearedValues时，当放大/缩小到特定点时，库会崩溃。
数据具有6个带有时间戳的小时值。我按小时对值进行分组和求和。时间戳和值永远不为空，也不是计算的总和。绘制图表后，我不会更新数据。
如果我从数据库中获取1000个值（~1000 / 6个数据点），则当缩小约5倍数据范围时，库会崩溃。如果我获取10000个值（~10000 / 6个数据点），则只要用户导航到图表所在的usercontrol，就会发生崩溃。如果我获取100000个值，则在大约放大到相同的minvalue和maxvalue时会发生崩溃。
但是当使用ChartValues而不是GearedValues或只使用几个数据点时，我可以尽可能接近放大并缩小到DateTime.minvalue。
我的view.xaml（几乎是示例，但使用ICommand RangeChangedCommand）：
<UserControl
[ ....]
xmlns:geared="clr-namespace:LiveCharts.Geared;assembly=LiveCharts.Geared">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"></RowDefinition>
<RowDefinition Height="*"></RowDefinition>
<RowDefinition Height="100"></RowDefinition>
</Grid.RowDefinitions>
<TextBlock Grid.Row="0"></TextBlock>
<lvc:CartesianChart Grid.Row="1"
Zoom="X"
DisableAnimations="True"
Hoverable="False">
<lvc:CartesianChart.Resources>
<Style TargetType="lvc:Separator">
<Setter Property="StrokeThickness" Value="2.5"></Setter>
<Setter Property="Stroke" Value="#E7E7E7"></Setter>
<Style.Triggers>
<Trigger Property="AxisOrientation" Value="X">
<Setter Property="IsEnabled" Value="False"></Setter>
</Trigger>
</Style.Triggers>
</Style>
</lvc:CartesianChart.Resources>
<lvc:CartesianChart.Series>
<geared:GLineSeries StrokeThickness="0"
Values="{Binding Values}"
Fill="#2194F1"
AreaLimit="0"
PointGeometry="{x:Null}"
LineSmoothness="0"/>
</lvc:CartesianChart.Series>
<lvc:CartesianChart.AxisX>
<lvc:Axis LabelFormatter="{Binding Formatter}" RangeChangedCommand="{Binding Axis_OnRangeChangedCommand}"
MinValue="{Binding From, Mode=TwoWay}" MaxValue="{Binding To, Mode=TwoWay}"
Separator="{x:Static lvc:DefaultAxes.CleanSeparator}"/>
</lvc:CartesianChart.AxisX>
</lvc:CartesianChart>
<lvc:CartesianChart Grid.Row="2" DisableAnimations="True"
ScrollMode="X"
ScrollHorizontalFrom="{Binding From, Mode=TwoWay}"
ScrollHorizontalTo="{Binding To, Mode=TwoWay}"
ScrollBarFill="#25303030"
DataTooltip="{x:Null}"
Hoverable="False"
Margin="20 10">
<lvc:CartesianChart.Resources>
<Style TargetType="lvc:Separator">
<Setter Property="IsEnabled" Value="False"></Setter>
</Style>
</lvc:CartesianChart.Resources>
<lvc:CartesianChart.Series>
<geared:GLineSeries Values="{Binding Values}"
Fill="Silver"
StrokeThickness="0"
PointGeometry="{x:Null}"
AreaLimit="0"/>
</lvc:CartesianChart.Series>
<lvc:CartesianChart.AxisX>
<lvc:Axis IsMerged="True"
LabelFormatter="{Binding Formatter, Mode=OneTime}"
Foreground="#98000000"
FontSize="22"
FontWeight="UltraBold"/>
</lvc:CartesianChart.AxisX>
<lvc:CartesianChart.AxisY>
<lvc:Axis ShowLabels="False" />
</lvc:CartesianChart.AxisY>
</lvc:CartesianChart>
</Grid>
我的VM.cs
class ScrollableVM : ObservableObject, IPageViewModel
{
public string Name => "Scrollable";
private double _from;
private double _to;
private Func<double, string> _formatter;
private ICommand _axis_OnRangeChanged;
public GearedValues<DateTimePoint> Values { get; set; }
//public ChartValues<DateTimePoint> Values { get; set; }
#region setget
public double From
{
get { return _from; }
set
{
SetProperty(ref _from, value);
}
}
public double To
{
get { return _to; }
set
{
SetProperty(ref _to, value);
}
}
public Func<double, string> Formatter
{
get { return _formatter; }
set
{
SetProperty(ref _formatter, value);
}
}
#endregion
public ScrollableVM()
{
var l = new List<DateTimePoint>();
using (/***getting data from db***/)
{
var q =(/***getting data from db***/).Take(1000).ToList();
var grouped = q.GroupBy(t => new DateTime(t.Stamp.Value.Year, t.Stamp.Value.Month, t.Stamp.Value.Day, t.Stamp.Value.Hour, 0, 0));
foreach (var item in grouped)
{
l.Add(new DateTimePoint((DateTime)item.Key, (double)item.Sum(x => x.value)));
}
}
//Crashes
//quality doesn't affect crashing
Values = l.AsGearedValues().WithQuality(Quality.High);
////Works
//Values = new GearedValues<DateTimePoint>() { new DateTimePoint(DateTime.Now, 0), new DateTimePoint(DateTime.Now.AddHours(1), 1) , new DateTimePoint(DateTime.Now.AddHours(2), 2) };
////Works
//Values = l.AsChartValues();
From = Values.Min(x => x.DateTime).Ticks;
To = Values.Max(x => x.DateTime).Ticks;
Formatter = x => new DateTime((long)x).ToString("yyyy");
}
private void Axis_OnRangeChanged(RangeChangedEventArgs eventargs)
{
var currentRange = eventargs.Range;
if (currentRange < TimeSpan.TicksPerDay * 2)
{
Formatter = x => new DateTime((long)x).ToString("t");
return;
}
if (currentRange < TimeSpan.TicksPerDay * 60)
{
Formatter = x => new DateTime((long)x).ToString("dd MMM yy");
return;
}
if (currentRange < TimeSpan.TicksPerDay * 540)
{
Formatter = x => new DateTime((long)x).ToString("MMM yy");
return;
}
Formatter = x => new DateTime((long)x).ToString("yyyy");
}
public ICommand Axis_OnRangeChangedCommand
{
get
{
if (_axis_OnRangeChanged == null)
{
_axis_OnRangeChanged = new RelayCommand(a => Axis_OnRangeChanged((RangeChangedEventArgs)a));
}
return _axis_OnRangeChanged;
}
}
}
view.xaml.cs只有带InitializeComponent（）的构造函数
例外细节：
System.ArgumentOutOfRangeException
HResult=0x80131502
Message=Specified argument was out of the range of valid values.
Parameter name: index
Source=WindowsBase
StackTrace:
at MS.Utility.FrugalStructList`1.Insert(Int32 index, T value)
at System.Windows.Media.PathSegmentCollection.Insert(Int32 index, PathSegment value)
at LiveCharts.Wpf.Points.HorizontalBezierPointView.DrawOrMove(ChartPoint previousDrawn, ChartPoint current, Int32 index, ChartCore chart)
at LiveCharts.SeriesAlgorithms.LineAlgorithm.Update()
at LiveCharts.ChartUpdater.Update(Boolean restartsAnimations, Boolean force)
at LiveCharts.Wpf.Components.ChartUpdater.UpdaterTick(Boolean restartView, Boolean force)
at LiveCharts.Wpf.Components.ChartUpdater.OnTimerOnTick(Object sender, EventArgs args)
at System.Windows.Threading.DispatcherTimer.FireTick(Object unused)
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)
at System.Windows.Threading.DispatcherOperation.InvokeImpl()
at System.Windows.Threading.DispatcherOperation.InvokeInSecurityContext(Object state)
at MS.Internal.CulturePreservingExecutionContext.CallbackWrapper(Object obj)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at MS.Internal.CulturePreservingExecutionContext.Run(CulturePreservingExecutionContext executionContext, ContextCallback callback, Object state)
at System.Windows.Threading.DispatcherOperation.Invoke()
at System.Windows.Threading.Dispatcher.ProcessQueue()
at System.Windows.Threading.Dispatcher.WndProcHook(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)
at System.Windows.Threading.Dispatcher.LegacyInvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)
at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg)
at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)
at System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame)
at System.Windows.Application.RunDispatcher(Object ignore)
at System.Windows.Application.RunInternal(Window window)
at System.Windows.Application.Run(Window window)
at System.Windows.Application.Run()
at medidata.App.Main() in ....\source\repos\medidata\medidata\obj\Debug\App.g.cs:line 51
版本：
我的代码/逻辑中是否有一些时髦的东西，或者这是我应该报告的错误？我没有发现其他人报告的类似问题。先感谢您。
好吧，这花了一个工作日，但我想我发现与我的实施相比，与官方的例子相比有什么不同......列表顺序。
如果我在调用AsGearedValues（）之前在x轴上按属性对原始数据进行排序，我就不会崩溃。这不是免费版本AsChartValues中的问题。我想这与虚拟化/优化有关，而AsGearedValues不够聪明，无法对列表本身进行排序以备将来使用。在文档中也没有提到这一点。我将在github上就此发表一个问题。
简单演示：
MainWindow.xaml.cs
using LiveCharts.Defaults;
using LiveCharts.Geared;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows;
namespace bughunt
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public IGearedValues Values { get; set; }
public MainWindow()
{
const int count = 1000;
//Not sorting causes crashes when zooming deep in and back
const bool SortBeforePassing = false;
var r = new Random();
var datepointlist = new List<DateTimePoint>();
for (int i = 0; i < count; i++)
{
datepointlist.Add(new DateTimePoint(DateTime.Now.AddHours(-i), (double)r.Next(1, 150)));
}
if (SortBeforePassing)
{
Values = datepointlist.OrderBy(x => x.DateTime).AsGearedValues().WithQuality(Quality.High);
}
else
{
Values = datepointlist.AsGearedValues().WithQuality(Quality.High);
}
DataContext = this;
InitializeComponent();
}
}
}
MainWindow.xaml
<Window x:Class="bughunt.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:bughunt"
xmlns:lvc="clr-namespace:LiveCharts.Wpf;assembly=LiveCharts.Wpf"
xmlns:geared="clr-namespace:LiveCharts.Geared;assembly=LiveCharts.Geared"
mc:Ignorable="d"
Title="MainWindow" Height="450" Width="800">
<Grid>
<lvc:CartesianChart Zoom="X"
DisableAnimations="True"
Hoverable="False">
<lvc:CartesianChart.Series>
<geared:GLineSeries
Values="{Binding Values}"
PointGeometry="{x:Null}"/>
</lvc:CartesianChart.Series>
</lvc:CartesianChart>
</Grid>
</Window>