MainWindow.xaml

<Window x:Class="MissingInheritedInterfaceMemberExample.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:MissingInheritedInterfaceMemberExample"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800"
        d:DataContext="{d:DesignInstance local:InterfaceB}"
        >
    <Window.DataContext>
        <local:Data/>
    </Window.DataContext>
    <WrapPanel>
        <StackPanel>
            <Label>Name</Label>
            <TextBox Text="{Binding Name}" />
        </StackPanel>
        <StackPanel>
            <Label>FirstName</Label>
            <!--  Member not found on InterfaceB -->
            <TextBox Text="{Binding FirstName}" />
        </StackPanel>
        <StackPanel>
            <Label>LastName</Label>
            <!--  Member not found on InterfaceB -->
            <TextBox Text="{Binding LastName}" />
        </StackPanel>
    </WrapPanel>
</Window>