PsUi

1.1.1

private/styles/Set-TabControlStyle.ps1

                                <#

.SYNOPSIS

    Applies themed styling to a TabControl with fixed tab row positions.

#>

function Set-TabControlStyle {

    [CmdletBinding()]

    param(

        [Parameter(Mandatory)]

        [System.Windows.Controls.TabControl]$TabControl

    )

    # Custom TabControl template that uses WrapPanel instead of TabPanel

    # WrapPanel doesn't reorder rows when a tab is selected

    # Uses DynamicResource for theme-aware colors

    $xaml = @"

<ControlTemplate xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

                 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

                 TargetType="TabControl">

    <Grid KeyboardNavigation.TabNavigation="Local">

        <Grid.RowDefinitions>

            <RowDefinition Height="Auto"/>

            <RowDefinition Height="*"/>

        </Grid.RowDefinitions>

        <!-- Tab header area using WrapPanel for stable row positions -->

        <Border Grid.Row="0"

                BorderBrush="{DynamicResource BorderBrush}"

                BorderThickness="0,0,0,1"

                Background="Transparent">

            <WrapPanel x:Name="HeaderPanel"

                       IsItemsHost="True"

                       HorizontalAlignment="Left"

                       Margin="8,0,0,0"

                       KeyboardNavigation.TabIndex="1"/>

        </Border>

        <!-- Content area -->

        <Border x:Name="ContentPanel"

                Grid.Row="1"

                Background="{DynamicResource WindowBackgroundBrush}"

                BorderBrush="{DynamicResource BorderBrush}"

                BorderThickness="0"

                KeyboardNavigation.TabNavigation="Local"

                KeyboardNavigation.DirectionalNavigation="Contained"

                KeyboardNavigation.TabIndex="2">

            <ContentPresenter x:Name="PART_SelectedContentHost"

                              ContentSource="SelectedContent"

                              Margin="0"/>

        </Border>

    </Grid>

</ControlTemplate>

"@

    # Check the alignment of the tab header, so it can be restored after the switch

    $oldPanel  = if ($TabControl.Template) { $TabControl.Template.FindName('HeaderPanel', $TabControl) }

    $alignment = if ($oldPanel) { $oldPanel.HorizontalAlignment }

    try { $TabControl.Template = [System.Windows.Markup.XamlReader]::Parse($xaml) }

    catch { Write-Verbose "Failed to apply TabControl template: $_" }

    if ($null -ne $alignment -and $TabControl.ApplyTemplate()) {

        $newPanel = $TabControl.Template.FindName('HeaderPanel', $TabControl)

        if ($newPanel) { $newPanel.HorizontalAlignment = $alignment }

    }

}