Wpf 依赖属性用法
我有一个工作附加行为,我想添加一个DP。我可以在XAML中设置该属性,但当我尝试访问它时,它是空的 解决办法是什么 干杯,Wpf 依赖属性用法,wpf,xaml,dependency-properties,attached-properties,Wpf,Xaml,Dependency Properties,Attached Properties,我有一个工作附加行为,我想添加一个DP。我可以在XAML中设置该属性,但当我尝试访问它时,它是空的 解决办法是什么 干杯, 贝里尔 xaml 在行为中使用常规的DependencyProperty,而不是附加属性,然后您可以执行以下操作 <Button Command="{Binding ContactCommand}"> <i:Interaction.Behaviors> <local:ContactCommandBehavior Reso
贝里尔 xaml
在
行为
中使用常规的DependencyProperty
,而不是附加属性,然后您可以执行以下操作
<Button Command="{Binding ContactCommand}">
<i:Interaction.Behaviors>
<local:ContactCommandBehavior ResourceKey="blah"/>
</i:Interaction.Behaviors>
</Button>
这是一个更好的语法。另外,请确保您尝试读取这些属性的代码只有在出现
onatached()
之后才能读取。您何时尝试访问它?你会等到“Loaded”事件被触发吗?这在语法上更好,但我的值仍然是空的。请参见文章末尾的编辑代码!
internal class ContactCommandBehavior : Behavior<ContentControl>
{
...
public static readonly DependencyProperty ResourceKeyProperty =
DependencyProperty.RegisterAttached("ResourceKey", typeof(string), typeof(ContactCommandBehavior));
public static string GetResourceKey(FrameworkElement element)
{
return (string)element.GetValue(ResourceKeyProperty);
}
public static void SetResourceKey(FrameworkElement element, string value)
{
element.SetValue(ResourceKeyProperty, value);
}
private void SetProperties(IHaveDisplayName detailVm)
{
//************
var key = GetResourceKey(AssociatedObject);
//************
....
}
}
public static readonly DependencyProperty ResourceKeyProperty =
DependencyProperty.Register("ResourceKey", typeof (string), typeof (ContactCommandBehavior));
public string ResourceKey
{
get { return (string)GetValue(ResourceKeyProperty); }
set { SetValue(ResourceKeyProperty, value); }
}
protected override void OnAttached() {
base.OnAttached();
if (AssociatedObject == null)
throw new InvalidOperationException("AssociatedObject must not be null");
AssociatedObject.DataContextChanged += OnDataContextChanged;
CultureManager.UICultureChanged += OnCultureChanged;
}
private void OnDataContextChanged(object sender, DependencyPropertyChangedEventArgs e) {
// do some setup stuff
SetProperties(vm)
}
private void SetProperties(IHaveDisplayName detailVm)
{
////////////////////////////////
var key = ResourceKey.Replace(TOKEN, cmType);
/////////////////////////////////
}
<Button Command="{Binding ContactCommand}">
<i:Interaction.Behaviors>
<local:ContactCommandBehavior ResourceKey="blah"/>
</i:Interaction.Behaviors>
</Button>