OxyPlot

Question

我有一个 PlotView，其高度绑定到视图模型中的属性 ModelHeight。

MainWindow.xaml

<oxy:PlotView x:Name="IOPlot" Model="{Binding IOPlotModel}" Height="{Binding ModelHeight, UpdateSourceTrigger=PropertyChanged}" Width="630">

ViewModel.cs

private double modelheight = 300;
public double ModelHeight { 
        get{return modelheight;}
        set { modelheight = value;
        RaisePropertyChanged("ModelHeight");
        RaisePropertyChanged("IOPlotModel");
        this.IOPlotModel.InvalidatePlot(false); 
        }
    }

问题是：它没有用数据绑定更新高度！高度仅在 PlotModel 启动期间更改一次。高度似乎是固定的（IOPlotModel.Height 始终等于 300，即使 ModelHeight 已更改）。有谁知道如何解决这个问题？

Answer 1

在这个最小的示例中，视图和视图模型是相同的 class MainWindow，因此 DataContext 在构造函数中设置为 this。通常应该是MVVM架构中的视图模型。

XAML:

<Window x:Class="PlotTest.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:oxyplot="http://oxyplot.org/wpf"
    mc:Ignorable="d"
    Title="MainWindow" 
    Height="450" 
    Width="800">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="30" />
            <RowDefinition Height="*" />
        </Grid.RowDefinitions>

        <TextBox x:Name="HeightTextBox"
                 Width="200"
                 TextChanged="HeightTextBox_TextChanged" />

        <oxyplot:PlotView Grid.Row="1"
                          Model="{Binding MyModel, UpdateSourceTrigger=PropertyChanged}"
                          Height="{Binding ModelHeight, UpdateSourceTrigger=PropertyChanged}" />
    </Grid>
</Window>

后面的代码：

using OxyPlot;
using System.ComponentModel;
using System.Windows;

namespace PlotTest
{
    public partial class MainWindow : Window, INotifyPropertyChanged
    {
        private double modelheight = 300;

        public MainWindow()
        {
            this.DataContext = this;
            this.MyModel = new PlotModel() { Background = OxyColors.AliceBlue };

            InitializeComponent();
        }

        public event PropertyChangedEventHandler PropertyChanged;

        public double ModelHeight
        {
            get { return modelheight; }
            private set
            {
                modelheight = value;
                this.RaisePropertyChanged("ModelHeight");
            }
        }

        public PlotModel MyModel { get; private set; }

        private void HeightTextBox_TextChanged(object sender, System.Windows.Controls.TextChangedEventArgs e)
        {
            if (double.TryParse(this.HeightTextBox.Text, out double height))
            {
                this.ModelHeight = height;
            }
        }

        private void RaisePropertyChanged(string propertyName = "")
        {
            this.PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

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OxyPlot - WPF PlotView does not update property

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OxyPlot - WPF PlotView 不更新属性