Come fare una larghezza StackPanel quella di un altro StackPanel?

Question

Ho due dockpanels che hanno ciascuno uno StackPanel sinistra.

La larghezza della inferiore StackPanel è determinata dalla larghezza del testo è in esso.

La larghezza della top StackPanel dovrebbe essere il stesso come la larghezza della inferiore StackPanel.

Ho cercato di impegnare la larghezza del StackPanel superiore alla larghezza del fondo StackPanel via ElementName, ma questo non funziona.

Come posso fare la larghezza superiore uguale alla larghezza del fondo?

<StackPanel>
    <DockPanel LastChildFill="True" Height="100" >
        <StackPanel Width="{Binding ElementName=LeftMenuText, Path=Width}" 
                    DockPanel.Dock="Left"
                    Background="Yellow">
            <TextBlock
                Text="This is some text."/>
        </StackPanel>
        <StackPanel DockPanel.Dock="Right"
                    Background="Orange">
        </StackPanel>
    </DockPanel>

    <DockPanel 
        Height="3"
        Background="Black"></DockPanel>

    <DockPanel LastChildFill="True" Height="100">
        <StackPanel Name="LeftMenuWrapper"
                    DockPanel.Dock="Left"
                    Background="Yellow">
            <TextBlock 
                    Text="This is some text that is longer."/>
        </StackPanel>
        <StackPanel DockPanel.Dock="Right"
                    Background="Blue">
        </StackPanel>
    </DockPanel>
</StackPanel>

Answer 1

associarlo al ActualWidth di LeftMenuWrapper:

 <StackPanel>
    <DockPanel LastChildFill="True" Height="100" >
        <StackPanel Width="{Binding ElementName=LeftMenuWrapper, Path=ActualWidth}" 
                    DockPanel.Dock="Left"
                    Background="Yellow">
            <TextBlock
                Text="This is some text."/>
        </StackPanel>
        <StackPanel DockPanel.Dock="Right"
                    Background="Orange">
        </StackPanel>
    </DockPanel>

    <DockPanel 
        Height="3"
        Background="Black"></DockPanel>

    <DockPanel LastChildFill="True" Height="100">
        <StackPanel Name="LeftMenuWrapper"
                    DockPanel.Dock="Left"
                    Background="Yellow">
            <TextBlock 
                    Text="This is some text that is longer."/>
        </StackPanel>
        <StackPanel DockPanel.Dock="Right"
                    Background="Blue">
        </StackPanel>
    </DockPanel>
</StackPanel>

Giusto per aggiungere al vostro arsenale un altro modo per fare questo. È inoltre possibile utilizzare la proprietà IsSharedScope di griglia:

<Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
   <StackPanel Grid.IsSharedSizeScope="True">
      <Grid Height="100">
         <Grid.ColumnDefinitions>
            <ColumnDefinition Width="Auto" SharedSizeGroup="TextHolder"/>
            <ColumnDefinition Width="*"/>
         </Grid.ColumnDefinitions>
         <Border Background="Yellow">
            <TextBlock Text="This is some text."/>
         </Border>
         <Border Grid.Column="1" Background="Orange"/>
      </Grid>
      <Border Height="3" Background="Black"/>
      <Grid Height="100">
         <Grid.ColumnDefinitions>
            <ColumnDefinition Width="Auto" SharedSizeGroup="TextHolder"/>
            <ColumnDefinition Width="*"/>
         </Grid.ColumnDefinitions>
         <Border Background="Yellow">
            <TextBlock Text="This is some text that is longer."/>
         </Border>
         <Border Grid.Column="1" Background="Blue"/>
      </Grid>
   </StackPanel>
</Page>

Answer 2

È possibile farlo utilizzando Grids con un SharedSizeGroup invece di DockPanels. Cioè.

<StackPanel Grid.IsSharedSizeScope="True">
    <Grid Height="100" >

        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="Auto" SharedSizeGroup="A"/>
            <ColumnDefinition Width="*" />
        </Grid.ColumnDefinitions>

        <StackPanel Grid.Column="0" Width="{Binding ElementName=LeftMenuText, Path=Width}"
                                DockPanel.Dock="Left"
                                Background="Yellow">
            <TextBlock
                    Text="This is some text."/>
        </StackPanel>
        <StackPanel Grid.Column="1" DockPanel.Dock="Right"
                                Background="Orange">
        </StackPanel>
    </Grid>

    <DockPanel
      Height="3"
      Background="Black"></DockPanel>

    <Grid Height="100">

        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="Auto" SharedSizeGroup="A"/>
            <ColumnDefinition Width="*" />
        </Grid.ColumnDefinitions>

        <StackPanel Grid.Column="0" Name="LeftMenuWrapper"
                                DockPanel.Dock="Left"
                                Background="Yellow">
            <TextBlock
                            Text="This is some text that is longer."/>
        </StackPanel>
        <StackPanel Grid.Column="1" DockPanel.Dock="Right"
                                Background="Blue">
        </StackPanel>
    </Grid>
</StackPanel>

Le cose fondamentali da ricordare sono per dare ad ogni colonna dentro le griglie di un SharedSizeGroup con lo stesso nome ( "A" in questo esempio), e aggiungere Grid.IsSharedSizeScope="True" ad un genitore condivisa delle Grids (la StackPanel contenente i Grids in questo esempio )