WPF依赖属性提供一个机制,可以获取依赖属性提供值的来源
其以BaseValueSource枚举表示
1.Default
public static readonly DependencyProperty WorkingTagProperty = DependencyProperty.Register(
"WorkingTag",
typeof(object),
typeof(CustomControl),
new UIPropertyMetadata("<working tag>"));
2.DefaultStyle和DefaultStyleTrigger(Style和StyleTrigger)
注意点:若即定义在外部程序集中的默认控件样式则为DefaultStyle和DefaultStyleTrigger,否则定义在本地项目(如在Application中重新定义控件样式,则为Style和StyleTrigger)
3.TemplateTrigger和ParentTemplateTrigger
在模板中触发
<ControlTemplate TargetType="{x:Type local:CustomControl}">
<Button x:Name="Part_Button" Content="{TemplateBinding Title}"
IsEnabled="{TemplateBinding IsEnabled}" Background="{TemplateBinding Background}" />
<ControlTemplate.Triggers>
<Trigger SourceName="Part_Button" Property="IsEnabled" Value="False">
<Setter Property="Title" Value="disable test text"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
4.ParentTemplate
当模板中有定义内部控件样式模板时,内部控件值变更由上级模板触发
下面TextBlock的Text的触发源为ParentTemplate
<Style TargetType="{x:Type local:CustomControl}">
<Setter Property="Title" Value="default test text" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type local:CustomControl}">
<ControlTemplate.Resources>
<Style TargetType="Button">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type Button}">
<TextBlock Text="{TemplateBinding Content}"/>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ControlTemplate.Resources>
<Border>
<Button x:Name="Part_Button" Content="{TemplateBinding Title}"
IsEnabled="{TemplateBinding IsEnabled}" Background="{TemplateBinding Background}" />
</Border>
<ControlTemplate.Triggers>
<Trigger SourceName="Part_Button" Property="IsEnabled" Value="False">
<Setter Property="Title" Value="disable test text"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
5.Local
即本地调用了SetValue方法
public object WorkingTag
{
get { return GetValue(WorkingTagProperty); }
set { SetValue(WorkingTagProperty, value); }
}
6.Inherited
属性继承是一个向下包容继承的关系
由属性继承值更改触发,如文字大小(FontSize)就是一个继承关系,更改根元素,那么子元素就全会更改
此功能也可以用来debug用,用来检测值是由何时修改的.
.net 4.0新增方法
DependencyObject ..::. SetCurrentValue 方法
这个方法类似SetValue方法,但SetCurrentValue 不会去修改属性值源(即何处修改属性值)
参考文档:
http://msdn.microsoft.com/en-us/library/ms743230.aspx
参考绑定时bug
http://blogs.msdn.com/b/vinsibal/archive/2009/03/24/the-control-local-values-bug.aspx
http://arbel.net/blog/archive/2009/11/04/local-values-in-dependencyobjects.aspx