39 lines
1.4 KiB
Markdown
39 lines
1.4 KiB
Markdown
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# 依赖属性
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- 节省实例对内存的开销
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- 属性值可以通过Binding依赖在其他对象上
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- 本身没有值，依赖Binding数据源获取值
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- 依赖属性需要依托依赖对象作为宿主
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- WPF的所有控件均是依赖对象，绝大多数属性也均为依赖属性
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定义依赖属性
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DependencyProperty是一种类型，所有的依赖属性都是这个类型，并且被public static readonly
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```csharp
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public class Student:DependencyObject
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{
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public static readonly DependencyProperty NameProperty=DependencyProperty.Register("Name",typeof(string),typeof(Student))
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//PropertyMetadata
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//CoerceValueCallback 依赖属性值被强制改变，调用此委托，关联一个影响函数
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//DefaultValue 依赖属性未被显式赋值时，若读取则获取此默认值，不设置会抛出异常
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//IsSealed 控制该数值是否可以更改，默认true
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//PropertyChangedCallback依赖属性的值被改变后此委托被调用，关联一个影响函数
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//clr属性包装依赖属性
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public string Name
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{
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get{return (string)GetValue(NameProperty)}
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Set{SetValue(NameProperty,value)}
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}
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public BindingExpressionBase SetBinding(DependencyProperty dp,BindingBase binding)
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{
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return BindingOperations.SetBinding(this,dp,binding)
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}
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}
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Student stu=new Student()
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stu.SetValue(Student.NameProperty,this.textBox.Text)
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textBox1.Text=(string)stu.GetValue(Student.NameProperty)
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```
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