我正在开发一个温度转换器作为测试项目。它具有三个应该相互通信的向上/向下控件。(右侧的标签仅用于调试。)当我通过旋转(例如摄氏)更改温度时,其相应的标签会正确更新,但我也希望开尔文和华氏值同时更改。但他们没有。为什么不?
目的是模型 (TempModel) 应该只保留一个值 (Kelvin)。其他需要时计算。我尝试了不同的方法来获取摄氏和华氏值。在这种情况下,我在模型中具有从私有 _Kelvin 变量计算其值的属性。它在启动时有效,但在我在运行时更改值时无效。
我也尝试对视图模型中的属性做类似的事情。
我相信解决方案相当简单,并且与绑定有关,但我仍然找不到它。
这是它的样子: 用户界面图像
这是查看 XAML 代码:
<Window x:Class="Temperature.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:extToolkit="http://schemas.microsoft.com/winfx/2006/xaml/presentation/toolkit/extended"
Title="Temperature converter" Height="183" Width="468">
<Grid VerticalAlignment="Stretch">
<Label Content="Kelvin" Height="28" HorizontalAlignment="Left" Margin="10,10,0,0" Name="label1" VerticalAlignment="Top" />
<extToolkit:DoubleUpDown Name="_KelvinUD" Increment="0.1" FormatString="F2" Value="{Binding Kelvin}" HorizontalAlignment="Left" Width="100" VerticalAlignment="Top" Margin="113,14,0,0" />
<Label Height="28" HorizontalAlignment="Left" Margin="279,10,0,0" Name="label4" VerticalAlignment="Top" Content="{Binding Kelvin}" />
<Label Content="Celsius" Height="28" HorizontalAlignment="Left" Margin="12,44,0,0" Name="label2" VerticalAlignment="Top" />
<extToolkit:DoubleUpDown Name="_CelsiusUD" Increment="0.1" FormatString="F2" Value="{Binding Celsius}" HorizontalAlignment="Left" Width="100" VerticalAlignment="Top" Margin="113,48,0,0" />
<Label Height="28" HorizontalAlignment="Left" Margin="279,44,0,0" Name="label5" VerticalAlignment="Top" Content="{Binding Celsius}" />
<Label Content="Fahrenheit" Height="28" HorizontalAlignment="Left" Margin="12,78,0,0" Name="label3" VerticalAlignment="Top" />
<extToolkit:DoubleUpDown Name="_FarenheitUD" Increment="0.1" FormatString="F2" Value="{Binding Fahrenheit}" HorizontalAlignment="Left" Width="100" VerticalAlignment="Top" Margin="113,82,0,0" />
<Label Height="28" HorizontalAlignment="Left" Margin="279,78,0,0" Name="label6" VerticalAlignment="Top" Content="{Binding Fahrenheit}" />
</Grid>
后面的代码:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
namespace Temperature
{
public partial class MainWindow : Window
{
private TempViewModel _viewModel = new TempViewModel();
TempViewModel ViewModel
{
get { return _viewModel; }
}
public MainWindow()
{
InitializeComponent();
base.DataContext = ViewModel;
}
}
}
该模型:
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ComponentModel;
namespace Temperature
{
public class TempModel
{
private double _kelvin;
public double Kelvin
{
get
{
return _kelvin;
}
set
{
_kelvin = value;
OnPropertyChanged("Kelvin");
}
}
public double Celsius
{
get
{
return _kelvin - 273.15;
}
set
{
_kelvin = value + 273.15;
OnPropertyChanged("Celsius");
}
}
public double Fahrenheit
{
get
{
return 9.0 / 5.0 * (_kelvin - 273.15) + 32;
}
set
{
_kelvin = 5.0 / 9.0 * (value - 32) + 273.15;
OnPropertyChanged("Fahrenheit");
}
}
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
}
}
视图模型:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Temperature
{
class TempViewModel
{
TempModel _tempModel;
public TempViewModel()
{
_tempModel = new TempModel
{
Kelvin = 300.15 // Initial value
};
}
public TempModel TempModel
{
get
{
return _tempModel;
}
set
{
_tempModel = value;
}
}
public double Kelvin
{
get
{
return _tempModel.Kelvin;
}
set
{
_tempModel.Kelvin = value;
}
}
public double Celsius
{
get
{
return _tempModel.Celsius;
}
set
{
_tempModel.Celsius = value;
}
}
public double Fahrenheit
{
get
{
return _tempModel.Fahrenheit;
}
set
{
_tempModel.Fahrenheit = value;
}
}
}
}