如何解决ScaleTransform 绑定但在绑定属性更改时不更新
我将 ViewScale 绑定到 Grid 的 ScaleTransform，当应用程序启动时它正确缩放 2。但是当我按 F12ViewScale 时，即使属性值更改，它也不会触发 ScaleTransform 更新。
代码如下：
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
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 test
{
public partial class MainWindow : Window
{
public event PropertyChangedEventHandler PropertyChanged;
protected void SetField<T> ( ref T field,T value,string propertyName )
{
if ( !EqualityComparer<T>.Default.Equals ( field,value ) )
{
field = value;
PropertyChanged?.Invoke ( this,new PropertyChangedEventArgs ( propertyName ) );
}
}
decimal viewScale = 2;
public decimal ViewScale
{
get => this.viewScale;
set => SetField ( ref this.viewScale,value,"ViewScale"
);
}
ObservableCollection<Coin> _coins;
public ObservableCollection<Coin> Coins { get => _coins; set => SetField ( ref _coins,nameof ( _coins ) ); }
public ICollectionView CollectionView;
public MainWindow ( )
{
this.Coins = new ObservableCollection<Coin> ( );
for ( int i = 0 ; i < 100 ; ++i )
this.Coins.Add ( new Coin ( "Coin 1",i ) );
this.DataContext = this;
InitializeComponent ( );
this.PreviewKeyDown += MainWindow_PreviewKeyDown;
}
void MainWindow_PreviewKeyDown ( object sender,KeyEventArgs e )
{
Console.WriteLine ( e.Key );
if ( e.Key == Key.Home )
{
this.dataGrid.ScrollIntoView ( this.dataGrid.Items [ this.dataGrid.Items.Count - 1 ] );
this.dataGrid.UpdateLayout ( );
this.dataGrid.ScrollIntoView ( this.dataGrid.Items [ 0 ] );
}
else if ( e.Key == Key.F12 )
{
this.ViewScale += 0.1m;
}
}
void MainWindow_KeyDown ( object sender,KeyEventArgs e )
{
}
}
public class Coin
{
public string Symbol { get; set; }
public int PNL { get; set; }
public SolidColorBrush Color2 { get; set; }
public Coin ( string symbol,int pnl )
{
this.Symbol = symbol;
this.PNL = pnl;
Random rnd = new Random ( );
Color c = Color.FromRgb ( ( byte ) rnd.Next ( 256 ),( byte ) rnd.Next ( 256 ),( byte ) rnd.Next ( 256 ) );
this.Color2 = new SolidColorBrush ( c );
}
}
}
XAML：
<Window x:Class="test.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:test"
mc:Ignorable="d"
Name="myMainWindow"
SizeToContent="Width"
DataContext="{Binding RelativeSource={RelativeSource Self}}"
Title="Profit Tracker"
WindowStyle="None"
Topmost="True"
Height="426">
<Window.Resources>
<Style x:Key="DataGridColumnSeparatorStyle" TargetType="DataGridCell">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate>
<Rectangle VerticalAlignment="Stretch" HorizontalAlignment="Stretch" Fill="#1e90ff"/>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<Style x:Key="DataGridColumnAlarmStyle" TargetType="DataGridCell">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate>
<Rectangle VerticalAlignment="Stretch" HorizontalAlignment="Stretch" Fill="#000000"/>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<Style TargetType="{x:Type DataGrid}">
<Setter Property="Background" Value="#FFF" />
<Setter Property="AlternationCount" Value="2" />
<Setter Property="BorderBrush" Value="Red" />
<Setter Property="BorderThickness" Value="0" />
</Style>
<Style x:Key="RowStyleWithAlternation" TargetType="DataGridRow">
<Setter Property="Background" Value="#141414"/>
<Setter Property="Foreground" Value="White"/>
<Setter Property="FontWeight" Value="Normal"/>
<Style.Triggers>
<Trigger Property="AlternationIndex" Value="0">
<Setter Property="Background" Value="#141414"/>
</Trigger>
<Trigger Property="AlternationIndex" Value="1">
<Setter Property="Background" Value="#282828"/>
</Trigger>
<Trigger Property="IsSelected" Value="True">
<Setter Property="BorderBrush" Value="Red" />
<Setter Property="BorderThickness" Value="1" />
<Setter Property="Margin" Value="-1,0" />
</Trigger>
<Trigger Property="IsMouseOver" Value="True">
<!--<Setter Property="BorderBrush" Value="#2eff00" />
<Setter Property="BorderThickness" Value="1" />-->
<Setter Property="Background" Value="Orange"/>
<!--<Setter Property="Margin" Value="-1,0" />-->
</Trigger>
</Style.Triggers>
</Style>
<Style TargetType="DataGridCell">
<Setter Property="TextBlock.TextAlignment" Value="Center" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type DataGridCell}">
<Grid Background="{TemplateBinding Background}">
<ContentPresenter VerticalAlignment="Stretch"/>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
<Setter Property="VerticalAlignment" Value="Stretch"/>
<Setter Property="Padding" Value="0"/>
<Setter Property="Margin" Value="0"/>
<Setter Property="BorderThickness" Value="0"/>
<Setter Property="FocusVisualStyle" Value="{x:Null}" />
<Style.Triggers>
<Trigger Property="IsSelected" Value="True">
<Setter Property="BorderBrush" Value="#1e90ff" />
<Setter Property="BorderThickness" Value="1" />
<!--<Setter Property="Background" Value="Red"/>-->
</Trigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding Column.DisplayIndex,RelativeSource={RelativeSource Self}}" Value="4"/>
</MultiDataTrigger.Conditions>
<MultiDataTrigger.Setters>
<Setter Property="VerticalAlignment" Value="Stretch"/>
</MultiDataTrigger.Setters>
</MultiDataTrigger>
<Trigger Property="IsSelected" Value="True">
<Setter Property="Background" Value="{x:Null}"/>
<Setter Property="BorderBrush" Value="{x:Null}"/>
</Trigger>
</Style.Triggers>
</Style>
<Style TargetType="DataGridColumnHeader">
<Setter Property="HorizontalContentAlignment" Value="Center" />
</Style>
<Style TargetType="{x:Type ProgressBar}">
<Setter Property="Padding" Value="0"/>
<Setter Property="Margin" Value="0"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="ProgressBar">
<Border BorderThickness="1" Background="#006400" CornerRadius="0" Padding="0">
<Grid x:Name="PART_Track">
<Rectangle x:Name="PART_Indicator" HorizontalAlignment="Left" Fill="#75001D" />
</Grid>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<CollectionViewSource Source="{Binding Coins}" IsLiveSortingRequested="True" x:Key="MyKey" />
</Window.Resources>
<Grid>
<Grid.LayoutTransform>
<ScaleTransform ScaleX="{Binding ViewScale,ElementName=myMainWindow}" ScaleY="{Binding ViewScale,ElementName=myMainWindow}" />
</Grid.LayoutTransform>
<DataGrid Name="dataGrid" ItemsSource="{Binding Source={StaticResource MyKey}}" SelectionMode="Single" GridLinesVisibility="None" HorizontalScrollBarVisibility="Hidden" RowHeaderWidth="0" IsReadOnly="True" CanUserAddRows="False" CanUserResizeColumns="False" CanUserResizeRows="False" AutoGenerateColumns="False" RowStyle="{StaticResource RowStyleWithAlternation}">
<DataGrid.Resources>
<SolidColorBrush x:Key="{x:Static SystemColors.HighlightBrushKey}" Color="Transparent" />
<SolidColorBrush x:Key="{x:Static SystemColors.ControlBrushKey}" Color="Transparent" />
</DataGrid.Resources>
<DataGrid.Columns>
<DataGridTemplateColumn MinWidth="0" Width="2" CellStyle="{StaticResource DataGridColumnSeparatorStyle}"/>
<DataGridTextColumn Header="PNL" Width="60" SortMemberPath="Balance.UnitPrice" Binding="{Binding Path=PNL}" />
<DataGridTemplateColumn MinWidth="0" Width="2" CellStyle="{StaticResource DataGridColumnSeparatorStyle}" CanUserSort="False"/>
<DataGridTemplateColumn Header="Price" Width="60" SortMemberPath="Price">
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<Grid>
<Grid>
<Border BorderBrush="#241C59" BorderThickness="1" CornerRadius="1" Background="#2D255B">
<Border BorderBrush="#206fb6" BorderThickness="4" CornerRadius="2" ClipToBounds="True" Margin="-1" HorizontalAlignment="Stretch">
<Border.Effect>
<BlurEffect Radius="10"/>
</Border.Effect>
</Border>
</Border>
<Border Margin="1" VerticalAlignment="Stretch" BorderThickness="0." Background="#69ABDB" HorizontalAlignment="Left" Width="30">
<Border BorderBrush="#38e2ff" BorderThickness="2" CornerRadius="2" ClipToBounds="False">
<Border.Effect>
<BlurEffect Radius="5"/>
</Border.Effect>
</Border>
</Border>
</Grid>
<TextBlock Text="25%" HorizontalAlignment="Center" VerticalAlignment="Center"/>
</Grid>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
<DataGridTemplateColumn Header="Vol BTC/h" Width="30" SortMemberPath="LastHourVolumeInBtc">
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<Grid>
<TextBlock Text="ABCDE" HorizontalAlignment="Center" VerticalAlignment="Center"/>
</Grid>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
<DataGridTemplateColumn Header="Vol BTC/h" Width="40">
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<Grid>
<ProgressBar Value="0.3" Minimum="0" Maximum="1"/>
<TextBlock Text="12345" HorizontalAlignment="Center" VerticalAlignment="Center"/>
</Grid>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
<DataGridTextColumn Header="Net BTC/m" Width="60"/>
</DataGrid.Columns>
</DataGrid>
</Grid>
</Window>
解决方法
为了提供属性更改通知，您必须在定义绑定属性的类型中implement the INotifyPropertyChanged interface。您错过了 MainWindow 代码隐藏中的这一部分，这也是您窗口的数据上下文。
public partial class MainWindow : Window,INotifyPropertyChanged
尽管您定义了 PropertyChanged 事件并且您的 SetField 方法正确引发了该事件，但如果您没有在类定义中声明接口，WPF 将不会意识到这一点。
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