How to stretch TextBox vertically?

Question

The Address in Tenant section, Description in Space as well as Head sections and Business of Lease section are multiline TextBox with these properties:

inputBox.AcceptsReturn = true;  
inputBox.TextWrapping = TextWrapping.Wrap;  
inputBox.HorizontalScrollBarVisibility = ScrollBarVisibility.Disabled;  
inputBox.VerticalScrollBarVisibility = ScrollBarVisibility.Auto;  
//inputBox.SetValue(ScrollViewer.CanContentScrollProperty, true);  
//inputBox.VerticalAlignment = VerticalAlignment.Stretch;  
inputBox.VerticalAlignment = VerticalAlignment.Top;  

When I resize the window all those TextBoxes stretch except the Address of Tenant section because I've this in MeasureOverride:

protected override Size MeasureOverride(Size availableSize) {  
    if (IsMultiline)   
        inputBox.Height = availableSize.Height == double.PositiveInfinity ? 100 : availableSize.Height;  
      
    container.Width = availableSize.Width;  
    container.Measure(availableSize);  
    return container.DesiredSize;  
}  

for the Address, I've set the Height to 100 otherwise I get System.ArgumentException: ''∞' is not a valid value for property 'Height'.' The Tenant view is inside a ScrollViewer with these properties:

var viewer = new ScrollViewer() {  
    HorizontalScrollBarVisibility = ScrollBarVisibility.Disabled,  
    VerticalScrollBarVisibility = ScrollBarVisibility.Auto,  
    //CanContentScroll = true,  
    Content = grid  
};  

and the RowDefinition of the the address TextBox is *.

How to stretch that vertically?

Answer 1

@DaisyTian-MSFT, this is the structure I'm using:

<Grid>  
    <Grid.Resources>  
        <Style TargetType="TextBox">  
            <Setter Property="Margin" Value="5 5 5 5"/>  
        </Style>  
        <Style TargetType="Border">  
            <Setter Property="Margin" Value="5"/>  
            <Setter Property="BorderThickness" Value="1"/>  
        </Style>  
    </Grid.Resources>  
    <Grid.ColumnDefinitions>  
        <ColumnDefinition/>  
        <ColumnDefinition/>  
        <ColumnDefinition/>  
    </Grid.ColumnDefinitions>  
    <Grid.RowDefinitions>  
        <RowDefinition/>  
        <RowDefinition/>  
    </Grid.RowDefinitions>  
    <Border BorderBrush="Black">  
        <ScrollViewer   
            VerticalScrollBarVisibility="Auto"  
            HorizontalScrollBarVisibility="Disabled">  
            <Grid>  
                <Grid.RowDefinitions>  
                    <RowDefinition Height="Auto"/>  
                    <RowDefinition Height="Auto"/>  
                    <RowDefinition Height="Auto"/>  
                    <RowDefinition Height="Auto"/>  
                    <RowDefinition Height="Auto"/>  
                    <RowDefinition Height="*"/>  
                    <RowDefinition Height="Auto"/>  
                    <RowDefinition Height="Auto"/>  
                    <RowDefinition Height="Auto"/>  
                    <RowDefinition Height="Auto"/>  
                </Grid.RowDefinitions>  
                <TextBox Grid.Row="0" />  
                <TextBox Grid.Row="1" />  
                <TextBox Grid.Row="2" />  
                <TextBox Grid.Row="3" />  
                <TextBox Grid.Row="4" />  
                <TextBox Grid.Row="5"   
                         AcceptsReturn="True" TextWrapping="Wrap"  
                         VerticalScrollBarVisibility="Auto"  
                         HorizontalScrollBarVisibility="Disabled"  
                         Text="TextBox that doesn't stretch vertically"/>  
                <TextBox Grid.Row="6" />  
                <TextBox Grid.Row="7" />  
                <Separator Grid.Row="8" Background="SkyBlue"/>  
                <TextBlock Grid.Row="9" Text="Error"/>  
            </Grid>  
        </ScrollViewer>  
    </Border>  

    <Border Grid.Row="1" BorderBrush="Blue">  
        <Grid>  
            <Grid.RowDefinitions>  
                <RowDefinition Height="Auto"/>  
                <RowDefinition/>  
            </Grid.RowDefinitions>  
            <TextBox Grid.Row="0" />  
            <TextBox Grid.Row="1"  
                 AcceptsReturn="True" TextWrapping="Wrap"  
                 VerticalScrollBarVisibility="Auto"  
                 HorizontalScrollBarVisibility="Disabled"  
                 Text="TextBox that does stretch vertically"/>  
        </Grid>  
    </Border>  
</Grid>  

Here in the shortened version, the 6th Multiline TextBox of the first Border doesn't stretch vertically as long as the VerticalScrollbar of the ScrollViewer is visible:

But the 2nd Multiline TextBox of the second Border does.