[英]Read-only attached property in trigger (WPF)
I have a problem with read-only attached property.我对只读附加属性有疑问。 I defined it in this way :
我是这样定义的:
public class AttachedPropertyHelper : DependencyObject
{
public static readonly DependencyPropertyKey SomethingPropertyKey = DependencyProperty.RegisterAttachedReadOnly("Something", typeof(int), typeof(AttachedPropertyHelper), new PropertyMetadata(0));
public static readonly DependencyProperty SomethingProperty = SomethingPropertyKey.DependencyProperty;
}
And I want to use it in XAML :我想在 XAML 中使用它:
<Trigger Property="m:AttachedPropertyHelper.Something" Value="0">
<Setter Property="FontSize" Value="20"/>
</Trigger>
But compiler doesnt want to work with it.但是编译器不想使用它。 In result, I have 2 errors:
结果,我有2个错误:
Cannot find the Style Property 'Something' on the type 'ReadonlyAttachedProperty.AttachedPropertyHelper'.
在“ReadonlyAttachedProperty.AttachedPropertyHelper”类型上找不到样式属性“Something”。 Line 11 Position 16.
第 11 行位置 16。
Property 'Something' was not found in type 'TextBlock'.
在类型 'TextBlock' 中找不到属性 'Something'。
I don't know if there is something special with your read-only attached property , but if you declare it in default manner it works:我不知道您的只读附加属性是否有什么特别之处,但是如果您以默认方式声明它,它会起作用:
public class AttachedPropertyHelper : DependencyObject
{
public static int GetSomething(DependencyObject obj)
{
return (int)obj.GetValue(SomethingProperty);
}
public static void SetSomething(DependencyObject obj, int value)
{
obj.SetValue(SomethingProperty, value);
}
// Using a DependencyProperty as the backing store for Something. This enables animation, styling, binding, etc...
public static readonly DependencyProperty SomethingProperty =
DependencyProperty.RegisterAttached("Something", typeof(int), typeof(AttachedPropertyHelper), new UIPropertyMetadata(0));
}
EDIT编辑
If you want the same as a readonly attached property you change it to:如果您想要与只读附加属性相同,请将其更改为:
public class AttachedPropertyHelper : DependencyObject
{
public static int GetSomething(DependencyObject obj)
{
return (int)obj.GetValue(SomethingProperty);
}
internal static void SetSomething(DependencyObject obj, int value)
{
obj.SetValue(SomethingPropertyKey, value);
}
private static readonly DependencyPropertyKey SomethingPropertyKey =
DependencyProperty.RegisterAttachedReadOnly("Something", typeof(int), typeof(AttachedPropertyHelper), new UIPropertyMetadata(0));
public static readonly DependencyProperty SomethingProperty = SomethingPropertyKey.DependencyProperty;
}
I want to note that at the current time it is better to use https://github.com/HavenDV/DependencyPropertyGenerator , the code will be extremely simple:我要注意,目前最好使用https://github.com/HavenDV/DependencyPropertyGenerator ,代码将非常简单:
[AttachedDependencyProperty<object, Grid>("Something", IsReadOnly = true)]
public static partial class GridExtensions
{
}
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