WindowsFormsTest/KeyBoard/MainWindow.xaml

<Window x:Class="KeyBoard.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:KeyBoard"
        mc:Ignorable="d"
        Title="MainWindow" Height="304" Width="1050"        
        Topmost="True" WindowStyle="ToolWindow" ShowInTaskbar="False"
        Deactivated="Window_Deactivated"
        Loaded="Window_Loaded">
    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="*"/>
            <ColumnDefinition Width="220"/>
        </Grid.ColumnDefinitions>
        <Grid Grid.Column="0">
            <Grid.RowDefinitions>
                <RowDefinition Height="*"/>
                <RowDefinition Height="*"/>
                <RowDefinition Height="*"/>
                <RowDefinition Height="*"/>
            </Grid.RowDefinitions>
            <Button Grid.Row="0" Content="1" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="10,0,0,0"/>
            <Button Grid.Row="0" Content="2" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="80,0,0,0"/>
            <Button Grid.Row="0" Content="3" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="150,0,0,0"/>
            <Button Grid.Row="0" Content="4" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="220,0,0,0"/>
            <Button Grid.Row="0" Content="5" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="290,0,0,0"/>
            <Button Grid.Row="0" Content="6" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="360,0,0,0"/>
            <Button Grid.Row="0" Content="7" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="430,0,0,0"/>
            <Button Grid.Row="0" Content="8" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="500,0,0,0"/>
            <Button Grid.Row="0" Content="9" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="570,0,0,0"/>
            <Button Grid.Row="0" Content="0" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="640,0,0,0"/>
            <Button Grid.Row="1" Content="1" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="10,0,0,0"/>
            <Button Grid.Row="1" Content="2" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="80,0,0,0"/>
            <Button Grid.Row="1" Content="3" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="150,0,0,0"/>
            <Button Grid.Row="1" Content="4" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="220,0,0,0"/>
            <Button Grid.Row="1" Content="5" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="290,0,0,0"/>
            <Button Grid.Row="1" Content="6" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="360,0,0,0"/>
            <Button Grid.Row="1" Content="7" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="430,0,0,0"/>
            <Button Grid.Row="1" Content="8" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="500,0,0,0"/>
            <Button Grid.Row="1" Content="9" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="570,0,0,0"/>
            <Button Grid.Row="1" Content="0" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="640,0,0,0"/>
            <Button Grid.Row="2" Content="1" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="10,0,0,0"/>
            <Button Grid.Row="2" Content="2" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="80,0,0,0"/>
            <Button Grid.Row="2" Content="3" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="150,0,0,0"/>
            <Button Grid.Row="2" Content="4" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="220,0,0,0"/>
            <Button Grid.Row="2" Content="5" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="290,0,0,0"/>
            <Button Grid.Row="2" Content="6" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="360,0,0,0"/>
            <Button Grid.Row="2" Content="7" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="430,0,0,0"/>
            <Button Grid.Row="2" Content="8" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="500,0,0,0"/>
            <Button Grid.Row="2" Content="9" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="570,0,0,0"/>
            <Button Grid.Row="2" Content="0" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="640,0,0,0"/>
            <Button Grid.Row="3" Content="1" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="10,0,0,0"/>
            <Button Grid.Row="3" Content="2" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="80,0,0,0"/>
            <Button Grid.Row="3" Content="3" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="150,0,0,0"/>
            <Button Grid.Row="3" Content="4" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="220,0,0,0"/>
            <Button Grid.Row="3" Content="5" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="290,0,0,0"/>
            <Button Grid.Row="3" Content="6" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="360,0,0,0"/>
            <Button Grid.Row="3" Content="7" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="430,0,0,0"/>
            <Button Grid.Row="3" Content="8" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="500,0,0,0"/>
            <Button Grid.Row="3" Content="9" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="570,0,0,0"/>
            <Button Grid.Row="3" Content="0" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="640,0,0,0"/>
        </Grid>
        <Grid Grid.Column="1">
            <Grid.RowDefinitions>
                <RowDefinition Height="*"/>
                <RowDefinition Height="*"/>
                <RowDefinition Height="*"/>
                <RowDefinition Height="*"/>
            </Grid.RowDefinitions>
            <Button Grid.Row="0" Tag="7"  Content="7" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="10,0,0,0" PreviewMouseDown="Button_PreviewMouseDown" />
            <Button Grid.Row="0" Content="8" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="80,0,0,0"/>
            <Button Grid.Row="0" Content="9" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="150,0,0,0"/>
            <Button Grid.Row="1" Content="4" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="10,0,0,0"/>
            <Button Grid.Row="1" Content="5" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="80,0,0,0"/>
            <Button Grid.Row="1" Content="6" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="150,0,0,0"/>
            <Button Grid.Row="2" Content="1" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="10,0,0,0"/>
            <Button Grid.Row="2" Content="2" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="80,0,0,0"/>
            <Button Grid.Row="2" Content="3" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="150,0,0,0"/>
            <Button Grid.Row="3" Content="0" HorizontalAlignment="Left" VerticalAlignment="Center" Width="60" Height="60" Margin="80,0,0,0"/>
        </Grid>
    </Grid>
</Window>