How to Use RelativeSource binding in WPF, wpfrelativesource

How to Use RelativeSource binding in WPF, wpfrelativesource

When binding WPF, when specifying the binding source, there is a way to use RelativeSource.

This method refers to the location relationship between the current element and the bound source.

First relationship: Self

For example, a StackPanel contains a TextBlock.

<TextBlock FontSize="18" FontWeight="Bold" Margin="10"                  Background="Red" Width="80" Height="{Binding RelativeSource={RelativeSource Self},Path=Width}">MultiBinding Sample</TextBlock>

To make the width and height of textbox the same, you can set the property Height = "{Binding RelativeSource = {RelativeSource Self}, Path = Width.

 

Second link:TemplatedParent

For example, write a style for a Button and change the Button to an elliptical type. At the same time, the background color of the ellipse must be the same as that of the Button.

<Style TargetType="{x:Type Button}">            <Setter Property="Background" Value="Green"/>            <Setter Property="Template">                <Setter.Value>                    <ControlTemplate TargetType="{x:Type Button}">                        <Grid>                            <Ellipse>                                <Ellipse.Fill>                                    <SolidColorBrush Color="{Binding Path=Background.Color,RelativeSource={RelativeSource TemplatedParent}}"/>                                </Ellipse.Fill>                            </Ellipse>                        </Grid>                    </ControlTemplate>                </Setter.Value>            </Setter>        </Style>

In this example, TemplateParent refers to the Button

 

Third link:AncestorType

Specify the binding source as a parent Element

<Grid>          <Label Background = {Binding Path=Background, RelativeSource={RelativeSource AncestorType={x:Type Grid}}}/>     </Grid>

In this example, the Label background color is the same as the Grid background color.