Layout a Form with StackPanel and Grid

   
            
<Window x:Class="Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="UseExpander" Height="300" Width="300">
    <Grid>
        <StackPanel Name="StackPanel1" Margin="0,0,0,0">
            <Expander Header="Name" Margin="0,0,0,0" Name="Expander1" IsExpanded="True">
                <StackPanel Margin="20,0,0,0">
                    <StackPanel Height="Auto" Width="Auto" Orientation="Horizontal">
                        <Label Height="25.96" Width="84">First Name</Label>
                        <TextBox Height="25" Width="147" />
                    </StackPanel>
                    <StackPanel Height="Auto" Width="Auto" Orientation="Horizontal">
                        <Label Height="25.96" Width="84">Last Name</Label>
                        <TextBox Height="25" Width="147" />
                    </StackPanel>
                </StackPanel>
            </Expander>
            <Separator />
            <Expander Header="Address" Margin="0,0,0,0" IsExpanded="True">
                <StackPanel Margin="20,0,0,0" >
                    <StackPanel Height="Auto" Width="Auto" Orientation="Horizontal">
                        <Label Height="25.96" Width="84">Street</Label>
                        <TextBox Height="25" Width="147" />
                    </StackPanel>
                    <StackPanel Height="Auto" Width="Auto" Orientation="Horizontal">
                        <Label Height="25.96" Width="84">City</Label>
                        <TextBox Height="25" Width="147" />
                    </StackPanel>
                    <StackPanel Height="Auto" Width="Auto" Orientation="Horizontal">
                        <Label Height="25.96" Width="84">State</Label>
                        <TextBox Height="25" Width="147" />
                    </StackPanel>
                    <StackPanel Height="Auto" Width="Auto" Orientation="Horizontal">
                        <Label Height="25.96" Width="84">Zip</Label>
                        <TextBox Height="25" Width="147" />
                    </StackPanel>
                </StackPanel>
            </Expander>
            <Separator />
        </StackPanel>
    </Grid>
</Window>