I have a window with tabs. On one of the tabs, I have a layout like below. (In fact it is more complicated, I have 4 text boxes in a row, and I have more rows.) How can I make the 3rd textbox have the width of the label + the width of the text box above, that is, to have them properly aligned ? The problem is that WPF widens the 3rd textbox, when I type text into it. Using hardcoded numbers for the sizes defeats the whole purpose of WPF. I could do that way 10 times faster in Windows Forms than in WPF.

Is there a better way, than using a grid for each set of consecutive small text boxes, having to skip the large ones from the grid, because putting them in messes up everything.

<Window x:Class="WpfApplication1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <Window.Resources>
        <Style TargetType="{x:Type Label}">
            <Setter Property="VerticalAlignment" Value="Center"/>
        </Style>
        <Style TargetType="{x:Type TextBox}">
            <Setter Property="VerticalAlignment" Value="Center"/>
            <Setter Property="Margin" Value="3"/>
        </Style>
        <Style x:Key="SmallTextBox" TargetType="{x:Type TextBox}"
               BasedOn="{StaticResource {x:Type TextBox}}">
            <Setter Property="Width" Value="50"/>
        </Style>
    </Window.Resources>

    <StackPanel VerticalAlignment="Top" HorizontalAlignment="Left"
                Width="{Binding ElementName=grid,Path=ActualWidth}"
                Grid.IsSharedSizeScope="True">
        <Grid Name="grid" HorizontalAlignment="Left">
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="Auto" SharedSizeGroup="c1"/>
                <ColumnDefinition Width="Auto" SharedSizeGroup="c2"/>
            </Grid.ColumnDefinitions>
            <Grid.RowDefinitions>
                <RowDefinition Height="Auto"/>
                <RowDefinition Height="Auto"/>
            </Grid.RowDefinitions>

            <Label Content="Foo:"/>
            <TextBox Grid.Column="1" Style="{StaticResource SmallTextBox}"/>
            <Label Grid.Row="1" Content="Foobar:"/>
            <TextBox Grid.Row="1" Grid.Column="1"
                     Style="{StaticResource SmallTextBox}"/>
        </Grid>

        <TextBox Grid.Row="1"/>

        <Grid Name="grid2" HorizontalAlignment="Left">
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="Auto" SharedSizeGroup="c1"/>
                <ColumnDefinition Width="Auto" SharedSizeGroup="c2"/>
            </Grid.ColumnDefinitions>

            <Label Content="Bar:"/>
            <TextBox Grid.Column="1" Style="{StaticResource SmallTextBox}"/>
        </Grid>
    </StackPanel>
</Window>