C# WPF如何侦听BindingBase对象?
我想创建一个特殊的C# WPF如何侦听BindingBase对象?,c#,wpf,binding,datatrigger,C#,Wpf,Binding,Datatrigger,我想创建一个特殊的DataTrigger来继承TriggerBase。与DataTrigger类似,在MyDataTrigger类中定义了类型为BindingBase的属性 我如何听它来追踪它的变化 public class MyDataTrigger : TriggerBase<FrameworkElement> { ... /// <summary> /// [Wrapper property for BindingProperty]
DataTrigger
来继承TriggerBase
。与DataTrigger
类似,在MyDataTrigger
类中定义了类型为BindingBase
的属性
我如何听它来追踪它的变化
public class MyDataTrigger : TriggerBase<FrameworkElement>
{
...
/// <summary>
/// [Wrapper property for BindingProperty]
/// <para>
/// Gets or sets the binding that produces the property value of the data object.
/// </para>
/// </summary>
public BindingBase Binding
{
get { return (BindingBase)GetValue(BindingProperty); }
set { SetValue(BindingProperty, value); }
}
public static readonly DependencyProperty BindingProperty =
DependencyProperty.Register("Binding",
typeof(BindingBase),
typeof(MyDataTrigger),
new FrameworkPropertyMetadata(null));
}
其中,DPListener\u ValueChanged
是一个EventHandler
委托。在这里,组件参数值是this.AssociatedObject好的,找到了
考虑到这一点,绑定不是DP。因此,我试图找到与DP相关的绑定:
Type type = Binding.GetType();
PropertyPath propertyPath = (PropertyPath)(type.GetProperty("Path").GetValue(Binding));
string propertyName = propertyPath.Path;
完整代码:
public class MyDataTrigger : TriggerBase<FrameworkElement>
{
...
public BindingBase Binding
{
get;
set;
}
protected override void OnAttached()
{
base.OnAttached();
if (Binding != null && this.AssociatedObject.DataContext != null)
//
// Adding a property changed listener..
//
Type type = Binding.GetType();
PropertyPath propertyPath = (PropertyPath)(type.GetProperty("Path").GetValue(Binding));
string propertyName = propertyPath.Path;
TypeDescriptor.GetProperties(this.AssociatedObject.DataContext).Find(propertyName, false).AddValueChanged(this.AssociatedObject.DataContext, PropertyListener_ValueChanged);
}
private void PropertyListener_ValueChanged(object sender, EventArgs e)
{
// Do some stuff here..
}
}
公共类MyDataTrigger:TriggerBase
{
...
公共绑定基绑定
{
收到
设置
}
受保护的覆盖无效附加()
{
base.onatached();
if(Binding!=null&&this.AssociatedObject.DataContext!=null)
//
//添加属性已更改的侦听器。。
//
Type=Binding.GetType();
PropertyPath PropertyPath=(PropertyPath)(type.GetProperty(“路径”).GetValue(绑定));
字符串propertyName=propertyPath.Path;
TypeDescriptor.GetProperties(this.AssociatedObject.DataContext).Find(propertyName,false).AddValueChanged(this.AssociatedObject.DataContext,PropertyListener\u ValueChanged);
}
私有void PropertyListener\u值已更改(对象发送方,事件参数e)
{
//在这里做些事情。。
}
}
关联的DP总是DataContext
,这是真的吗?这不能被标记为一般答案。这里只考虑BindingBase
的Path
属性。(例如,不是XPath
)。有什么建议吗?使用。。。var propertyName=((Binding)this.Binding).Path.Path;
public class MyDataTrigger : TriggerBase<FrameworkElement>
{
...
public BindingBase Binding
{
get;
set;
}
protected override void OnAttached()
{
base.OnAttached();
if (Binding != null && this.AssociatedObject.DataContext != null)
//
// Adding a property changed listener..
//
Type type = Binding.GetType();
PropertyPath propertyPath = (PropertyPath)(type.GetProperty("Path").GetValue(Binding));
string propertyName = propertyPath.Path;
TypeDescriptor.GetProperties(this.AssociatedObject.DataContext).Find(propertyName, false).AddValueChanged(this.AssociatedObject.DataContext, PropertyListener_ValueChanged);
}
private void PropertyListener_ValueChanged(object sender, EventArgs e)
{
// Do some stuff here..
}
}