我有我的Xaml如下
<Window.Resources>
<SolidColorBrush x:Key="BrushMe" Color="Red"/>
<SolidColorBrush x:Key="FreezeBrushMe" po:Freeze="true" Color="Yellow"/>
</Window.Resources>
<StackPanel>
<Button Background="{StaticResource BrushMe}">Static</Button>
<Button Background="{DynamicResource BrushMe}">Dynamic</Button>
<Button Click="Button_Click">ChangeColorProperty</Button>
<Button Click="Button1_Click">ChangeBrushObject</Button>
<!--<Button Background="{StaticResource NotExistResource}" Click="Button_Click_1">GenerateResourceForStatic</Button>-->
<Button Background="{DynamicResource NotExistResource}" Click="Button_Click_1">GenerateResourceForDynamic</Button>
<Button Background="Green" Click="Button_Click_1">FixedBrush</Button>
<Button Background="{StaticResource FreezeBrushMe}">FreezeBrushStatic</Button>
<Button Background="{DynamicResource FreezeBrushMe}">FreezeBrushDynamic</Button>
<Button Click="Button_Click_2">ChangeFreezeColorProperty</Button>
<Button Click="Button_Click_3">ChangeFreezeBrushObject</Button>
</StackPanel>
在我的代码背后,它看起来像
private void Button_Click(object sender, RoutedEventArgs e)
{
SolidColorBrush brush = (SolidColorBrush)this.FindResource("BrushMe");
brush.Color = Colors.Blue;
this.Resources["BrushMe"] = brush;
}
private void Button1_Click(object sender, EventArgs e)
{
SolidColorBrush newBrush = new SolidColorBrush(Colors.Yellow);
this.Resources["BrushMe"] = newBrush;
}
private void Button_Click_1(object sender, RoutedEventArgs e)
{
this.Resources.Add("NotExistResource", new SolidColorBrush(Colors.Green));
}
private void Button_Click_2(object sender, RoutedEventArgs e)
{
SolidColorBrush brush = (SolidColorBrush)this.FindResource("FreezeBrushMe");
brush.Color = Colors.Blue;
this.Resources["FreezeBrushMe"] = brush;
}
private void Button_Click_3(object sender, RoutedEventArgs e)
{
SolidColorBrush newBrush = new SolidColorBrush(Colors.Red);
this.Resources["FreezeBrushMe"] = newBrush;
}
我的问题是,如果我先单击ChangeBrushObject按钮,它会将动态按钮更改为黄色,然后单击ChangeColorProperty按钮,它只会将动态按钮更改为蓝色,而不会影响静态按钮 .
但是,如果我单独单击ChangeColorProperty按钮,它会将静态和动态按钮更改为蓝色 .
它为什么会这样?尝试将新对象分配给控件引用为静态资源的资源时,WPF不会抛出任何警告?
我还测试了Dynamic Resource引用的不存在的资源 . 正如预期的那样,如果StaticResource引用了一个不存在的资源,Xaml将在编译时抱怨,而DynamicResource则不会 . 但是,如果单击GenerateResourceForDynamic按钮,它会将绿色显示为背景,但随后会消失,然后重新出现并重复 . 为什么会这样?
Edit: 再次添加了冻结资源,奇怪的行为 . 如果我单击ChangeFreezeColorProperty按钮,它将通过异常 . 如果单独单击ChangeFreezeBrushObject,它将更改FreezeBrushDynamic按钮颜色 . 但是,如果单击ChangeFreezeBrushObject然后单击ChangeFreezeColorProperty,则不会引发任何异常 .
我认为制作资源冻结会使与资源链接的对象的属性成为只读 . 这就是为什么在更改属性时,它会通过异常抱怨readonly状态 . 但是冻结并不能阻止我们改变对象本身 .