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WPF中Binding

news 来源：原创 2025/5/5 7:01:33

绑定ViewModel中的数据

添加数据上下文

方法一：在XAML中添加

<Window.DataContext><local:MainWindowViewModel />
</Window.DataContext>

方法二：在界面层的cs文件中添加

this.DataContext = new MainWindowViewModel();

绑定

public string Message { get; set; } = "Hello World";

<TextBlock Text="{Binding Path=Message}" Margin="10"/>
//简写此一个参数默认是Path
<TextBlock Text="{Binding Message}" Margin="10"/>
//什么都不屑默认绑定DataContext
<TextBlock Text="{Binding}" Margin="10"/>

绑定资源字典

简单的绑定资源字典的数据

<Window.DataContext><local:MainWindowViewModel />
</Window.DataContext>
<Window.Resources><sys:String x:Key="str">Hello, World</sys:String>
</Window.Resources>
<Grid><TextBlock Text="{Binding Source={StaticResource str}}" Margin="10"/>//简写<TextBlock Text="{staticResource str}" Margin="10"/>//绑定动态资源只能这样简写，写完整会报错<TextBlock Text="{DynamicResource str}" Margin="10"/>
</Grid>

绑定cs文件中资源字典的数据

先定义一个类

class MyResourece
{public string Message { get; } = "Public Property";public static string StaticString = "Static String";public const string ConstString = "Const String";
}

把类读取到资源字典

<Window.Resources><local:MyResourece x:Key="mysource" />
</Window.Resources>

对于静态，常量，enum，都得用x：Staic来访问，普通的资源可以用StaticResource

<TextBlock Text="{Binding Source={StaticResource mysource},Path=Message}"/>
//静态和常量得用x：Static访问
<TextBlock Grid.Row="1" Text="{Binding Source={x:Static local:MyResourece.ConstString}}" />
<TextBlock Grid.Row="2" Text="{Binding Source={x:Static local:MyResourece.StaticString}}" />

绑定控件

ElementName

<StackPanel><TextBox x:Name="txt" /><TextBlock Text="{Binding ElementName=txt, Path=Text}" />
</StackPanel>

x:Reference

当ElementName失效时可以用x：Reference，这是通用什么情况下都可以用

TextBlock Text="{Binding Source={x:Reference Name=txt},Path=Text}" />

RelativeSource

<TextBlock Text="{Binding RelativeSource={RelativeSource Mode=FindAncestor,AncestorType=Window},Path=Top}" />

我想读取到tag1的写法,当有多个相同的属性可以用AncestorLevel=3，标识找到父级第三个Grid

<Grid Tag="tag1"><Grid Tag="tag2"><Grid Tag="tag3"><TextBlock Text="{Binding RelativeSource={RelativeSource Mode=FindAncestor,AncestorType=Grid,AncestorLevel=3},Path=Tag}" /></Grid></Grid>
</Grid>

用ReletiveSource绑定同级别控件

<StackPanel><TextBox /><TextBlock Text="{Binding RelativeSource={RelativeSource AncestorType=StackPanel},Path=Children[0].Text}" />
</StackPanel>

绑定自己的写法四种写法

<TextBlock Text="{Binding RelativeSource={RelativeSource Mode=Self},Path=ActualWidth}" />

<TextBlock Text="{Binding RelativeSource={RelativeSource Self},Path=ActualWidth}" />

<TextBlock Text="{Binding RelativeSource={x:Static RelativeSource.Self},Path=ActualWidth}" />

<TextBlock Text="{Binding RelativeSource={RelativeSource 2},Path=ActualWidth}" />

绑定模板的属性，两种先给发等价

<StackPanel><Label Padding="10"><Label.Template><ControlTemplate TargetType="Label"><Border Padding="{Binding RelativeSource={RelativeSource Mode=TemplatedParent},Path=Padding}"><ContentPresenter /></Border></ControlTemplate></Label.Template></Label>
</StackPanel>

<StackPanel><Label Padding="10"><Label.Template><ControlTemplate TargetType="Label"><Border><ContentPresenter Margin="{TemplateBinding Padding}" /></Border></ControlTemplate></Label.Template></Label>
</StackPanel>

StringFormat

StringFormat可以指定格式，:F3表示小数点后三位小数

<TextBlock Text="{Binding RelativeSource={RelativeSource AncestorType=Window},Path=Top,StringFormat='Top:{0:F3}'}" />

MultiBinding

<StackPanel><TextBlock><TextBlock.Text><MultiBinding StringFormat="Pos:{0},{1}"><Binding Path="Top"RelativeSource="{RelativeSource AncestorType=Window}" /><Binding Path="Left"RelativeSource="{RelativeSource AncestorType=Window}" /></MultiBinding></TextBlock.Text></TextBlock>
</StackPanel>

有Content属性的控件，可以用ContentStringFormat

<StackPanel><Label Content="{Binding RelativeSource={RelativeSource AncestorType=Window},Path=Top}"ContentStringFormat="Top:{0:F3}" />
</StackPanel>

FallbackValue和TargetNullValue

FallbackValue在没有绑定成功时优先显示

TargetNullValue在绑定的值为空时优先显示

<Label Content="{Binding Message,FallbackValue=dasdaa,TargetNullValue=asdasd}"/>

对比

RelativeSource、ElementName、x:Reference中前两者依赖对象树寻找关系，x:Reference可以从文档搜索，前两者绑定失效可以用x:Reference

x:Reference的缺陷，无法绑定自己的父级

BindingProxy

public class BindingProxy : Freezable
{#region Overrides of Freezableprotected override Freezable CreateInstanceCore(){return new BindingProxy();}#endregionpublic object Data{get { return (object)GetValue(DataProperty); }set { SetValue(DataProperty, value); }}// Using a DependencyProperty as the backing store for Data.  This enables animation, styling, binding, etc...public static readonly DependencyProperty DataProperty =DependencyProperty.Register("Data", typeof(object), typeof(BindingProxy), new UIPropertyMetadata(null));
}

<Window.Resources><local:MyResourece x:Key="mysource" /><local:BindingProxy x:Key="mybtn"Data="{Binding ElementName=btn}" />
</Window.Resources>
<StackPanel><Button Name="btn"Content="Click Me"><Button.ToolTip><ToolTip><StackPanel><TextBlock Text="{Binding RelativeSource={RelativeSource AncestorType=Button},Path=Content}" /><TextBlock Text="{Binding Source={StaticResource mybtn},Path=Data.Content}" /></StackPanel></ToolTip></Button.ToolTip></Button>
</StackPanel>