Some tips

1. UIPropertyMetadata and FrameworkPropertyMetadata

• UIPropertyMetaData Provides property metadata for non-framework properties that do have rendering/user interface impact at the core level.

构造函数： 

 UIPropertyMetadata()
 UIPropertyMetadata(default Object)  
 UIPropertyMetadata(PropertyChangedCallback) 
 UIPropertyMetadata(default Object, PropertyChangedCallback) 
 UIPropertyMetadata(default Object, PropertyChangedCallback, CoerceValueCallback) 

 UIPropertyMetadata(Object, PropertyChangedCallback, CoerceValueCallback, Boolean) a Boolean used to disable animations on the property.

UIElement主要负责路由事件，命令帮定，布局，焦点的可视对象基类。

 

• FrameworkPropertyMetadata:UIPropertyMetadata

FrameworkPropertyMetadata Reports or applies metadata for a dependency property, specifically adding framework-specific property system characteristics.

 FrameworkPropertyMetadata 最大的优势是有一个FrameworkPropertyMetadataOptions在构造函数中 ，

These options specify characteristics of the dependency property that interact with systems such as layout or data binding. Can be Combination of optiongs below:

 Member      name Description
 None   ：  No options are specified; the dependency property uses the default behavior of the Windows Presentation           Foundation (WPF) property system. 
 AffectsMeasure: The measure pass of layout compositions is affected by value changes to this dependency property. 
 AffectsArrange: The arrange pass of layout composition is affected by value changes to this dependency property. 
 AffectsParentMeasure: The measure pass on the parent element is affected by value changes to this dependency property. 
 AffectsParentArrange: The arrange pass on the parent element is affected by value changes to this dependency property. 
 AffectsRender :Some aspect of rendering or layout composition (other than measure or arrange) is affected by value changes to this dependency property.  当属性值改变时，要求子元素重新呈现。
 Inherits :The values of this dependency property are inherited by child elements. 
 OverridesInheritanceBehavior: The values of this dependency property span separated trees for purposes of property value inheritance. 
 NotDataBindable: Data binding to this dependency property is not allowed. 
 BindsTwoWayByDefault: The BindingMode for data bindings on this dependency property defaults to TwoWay. 
 Journal: The values of this dependency property should be saved or restored by journaling processes, or when navigating by Uniform resource identifiers (URIs). 
 SubPropertiesDoNotAffectRender:The subproperties on the value of this dependency property do not affect any aspect of rendering. 

使用：FrameworkPropertyMetadataOptions.AffectsRender |
      FrameworkPropertyMetadataOptions.BindsTwoWayByDefault),
FrameworkElement支持样式，数据帮定，资源和一些通用机制的windows控件，如tooltip, contextmenu等。

 

2。 How to new line in xaml string attribute

<LineBreak/>   or