原文:
WPF整理--动态绑定到Logical Resource
“What happens if we replace a
specific resource? Would that be reflected in all objects using the resource? And if not, can we
bind to the resource dynamically?”
接上篇博文，如果我们需要在C#代码中动态替换某个logical resource，我们该如何做呢？
如，Window的Resources属性赋值如下：
<Window x:Class="DynamicallyBindingToALogicalResource.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525">
<Window.Resources>
<LinearGradientBrush x:Key="brush1">
<GradientStop Offset="0.3" Color="Yellow"/>
<GradientStop Offset="0.7" Color="Brown"/>
</LinearGradientBrush>
</Window.Resources>
<StackPanel>
<Rectangle Height="100" Stroke="Pink" StrokeThickness="20" Fill="{StaticResource brush1}"/>
<Button x:Name="button1" Content="Replace Brush" Height="100" Click="OnReplaceBrush"/>
</StackPanel>
</Window>
Button Click事件中Replace Window的key为"brush1"的Resources
private void OnReplaceBrush(object sender, RoutedEventArgs e)
{
var brush = new LinearGradientBrush();
brush.GradientStops.Add(new GradientStop(Colors.Pink, 0.2));
brush.GradientStops.Add(new GradientStop(Colors.Blue, 0.5));
brush.GradientStops.Add(new GradientStop(Colors.Violet, 0.8));
this.Resources["brush1"] = brush;
}
点击按钮，程序没有任何反应，可以通过DynamicResource这个markup extension实现。
“Run the application and click on the button. You'll notice nothing happens. Now
change the StaticResource markup extension to DynamicResource on the
Rectangle:”
<Rectangle Height="100" Stroke="Violet" StrokeThickness="20" Fill="{DynamicResource brush1}" />
程序运行如下：
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点击Button后：
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附XAML和C#代码：
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<Window x:Class="DynamicallyBindingToALogicalResource.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525">
<Window.Resources>
<LinearGradientBrush x:Key="brush1">
<GradientStop Offset="0.3" Color="Yellow"/>
<GradientStop Offset="0.7" Color="Brown"/>
</LinearGradientBrush>
</Window.Resources>
<StackPanel>
<Rectangle Height="100" Stroke="Pink" StrokeThickness="20" Fill="{StaticResource brush1}"/>
<Rectangle Height="100" Stroke="Violet" StrokeThickness="20" Fill="{DynamicResource brush1}" />
<Button x:Name="button1" Content="Replace Brush" Height="100" Click="OnReplaceBrush"/>
</StackPanel>
</Window>
View Code
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using System;
using System.Collections.Generic;
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 DynamicallyBindingToALogicalResource
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
private void OnReplaceBrush(object sender, RoutedEventArgs e)
{
var brush = new LinearGradientBrush();
brush.GradientStops.Add(new GradientStop(Colors.Pink, 0.2));
brush.GradientStops.Add(new GradientStop(Colors.Blue, 0.5));
brush.GradientStops.Add(new GradientStop(Colors.Violet, 0.8));
this.Resources["brush1"] = brush;
}
}
}
View Code
