Window_NumPad.xaml

<Window x:Class="FLY.UI.OSK.Window_NumPad"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        WindowStyle="None" ResizeMode="NoResize" WindowStartupLocation="CenterScreen"
        Title="Window_NumPad" Height="400" Width="350" Background="#525a65" Loaded="Window_Loaded">
    <Window.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <ResourceDictionary Source="MaterialDesignIcons.xaml"/>
            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </Window.Resources>
    <Grid>
        <Grid.Resources>
            <SolidColorBrush x:Key="Color_light" Color="#f4f4f4"/>
            <SolidColorBrush x:Key="Color_dark" Color="#8e9aa8"/>
            <Style TargetType="TextBlock" x:Key="TextBlockStyle_abc">
                <Setter Property="Foreground"  Value="#444e57" />
                <Setter Property="FontSize"  Value="20" />
                <Setter Property="FontFamily"  Value="Microsoft Sans Serif" />
                <Setter Property="TextAlignment"  Value="Left" />
            </Style>
            <Style TargetType="Button" x:Key="ButtonStyle_key">
                <Setter Property="Margin" Value="3"/>
                <Setter Property="Template">
                    <Setter.Value>
                        <ControlTemplate TargetType="{x:Type Button}">
                            <StackPanel Orientation="Vertical">
                                <Border Background="{TemplateBinding Background}" Height="{TemplateBinding ActualHeight}" Width="{TemplateBinding ActualWidth}" BorderThickness="2" CornerRadius="3">
                                    <Grid>
                                        <Grid.RowDefinitions>
                                            <RowDefinition Height="50*"/>
                                            <RowDefinition Height="150*"/>
                                            <RowDefinition Height="50*"/>
                                        </Grid.RowDefinitions>
                                        <Grid.ColumnDefinitions>
                                            <ColumnDefinition Width="50*"/>
                                            <ColumnDefinition Width="150*"/>
                                            <ColumnDefinition Width="50*"/>
                                        </Grid.ColumnDefinitions>
                                        <Viewbox Grid.Row="1" Grid.Column="1" >
                                            <ContentPresenter RecognizesAccessKey="True" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
                                        </Viewbox>
                                    </Grid>

                                </Border>
                            </StackPanel>
                            <ControlTemplate.Triggers>
                                <Trigger Property="IsKeyboardFocused" Value="true">
                                </Trigger>
                                <Trigger Property="IsEnabled" Value="false">
                                </Trigger>
                                <Trigger Property="IsPressed" Value="true">
                                    <Setter Property="Opacity" Value="0.5"/>
                                </Trigger>
                            </ControlTemplate.Triggers>
                        </ControlTemplate>
                    </Setter.Value>
                </Setter>
            </Style>
            <Style TargetType="Button" x:Key="ButtonStyle_abc" BasedOn="{StaticResource ButtonStyle_key}">
                <Setter Property="Background" Value="{StaticResource Color_light}"/>
            </Style>
            <Style TargetType="Button" x:Key="ButtonStyle_opt" BasedOn="{StaticResource ButtonStyle_key}">
                <Setter Property="Background" Value="{StaticResource Color_dark}"/>
            </Style>
        </Grid.Resources>
        <Grid.RowDefinitions>
            <RowDefinition Height="57*" />
            <RowDefinition Height="200*" />
        </Grid.RowDefinitions>
        <Border Background="White" Margin="6" CornerRadius="3" MouseDown="Border_MouseDown">
            <Viewbox Margin="3" HorizontalAlignment="Right" VerticalAlignment="Center" >
                <TextBlock x:Name="textblock_result" Text="{Binding Result}" Foreground="Black" FontWeight="Bold" FontSize="30" />
            </Viewbox>
        </Border>
        <Grid Grid.Row="1" Margin="3">
            <Grid.RowDefinitions>
                <RowDefinition />
                <RowDefinition />
                <RowDefinition  />
                <RowDefinition  />
            </Grid.RowDefinitions>
            <Grid.ColumnDefinitions>
                <ColumnDefinition/>
                <ColumnDefinition/>
                <ColumnDefinition/>
                <ColumnDefinition/>
            </Grid.ColumnDefinitions>

            <Button Grid.Row="0" Grid.Column="0" Style="{StaticResource ButtonStyle_abc}" Click="button_7_Click">
                <TextBlock Text="7" Style="{StaticResource TextBlockStyle_abc}" />
            </Button>
            <Button Grid.Row="0" Grid.Column="1" Style="{StaticResource ButtonStyle_abc}" Click="button_8_Click">
                <TextBlock Text="8" Style="{StaticResource TextBlockStyle_abc}" />
            </Button>
            <Button Grid.Row="0" Grid.Column="2" Style="{StaticResource ButtonStyle_abc}" Click="button_9_Click">
                <TextBlock Text="9" Style="{StaticResource TextBlockStyle_abc}" />
            </Button>
            <Button Grid.Row="1" Grid.Column="0" Style="{StaticResource ButtonStyle_abc}" Click="button_4_Click">
                <TextBlock Text="4" Style="{StaticResource TextBlockStyle_abc}" />
            </Button>
            <Button Grid.Row="1" Grid.Column="1" Style="{StaticResource ButtonStyle_abc}" Click="button_5_Click">
                <TextBlock Text="5" Style="{StaticResource TextBlockStyle_abc}" />
            </Button>
            <Button Grid.Row="1" Grid.Column="2" Style="{StaticResource ButtonStyle_abc}" Click="button_6_Click">
                <TextBlock Text="6" Style="{StaticResource TextBlockStyle_abc}" />
            </Button>
            <Button Grid.Row="2" Grid.Column="0" Style="{StaticResource ButtonStyle_abc}" Click="button_1_Click">
                <TextBlock Text="1" Style="{StaticResource TextBlockStyle_abc}" />
            </Button>
            <Button Grid.Row="2" Grid.Column="1" Style="{StaticResource ButtonStyle_abc}" Click="button_2_Click">
                <TextBlock Text="2" Style="{StaticResource TextBlockStyle_abc}" />
            </Button>
            <Button Grid.Row="2" Grid.Column="2" Style="{StaticResource ButtonStyle_abc}" Click="button_3_Click">
                <TextBlock Text="3" Style="{StaticResource TextBlockStyle_abc}" />
            </Button>
            <Button Grid.Row="0" Grid.Column="3" Style="{StaticResource ButtonStyle_opt}" Click="button_backspace_Click">
                <Path Style="{StaticResource PathStyle_backspace}" Fill="{StaticResource Color_light}" />
            </Button>
            <Button Grid.Row="1" Grid.Column="3" Style="{StaticResource ButtonStyle_opt}" Click="button_close_Click">
                <Path Style="{StaticResource PathStyle_window-close}" Fill="{StaticResource Color_light}" />
            </Button>
            <Button Grid.Row="2" Grid.Column="3" Grid.RowSpan="2" Style="{StaticResource ButtonStyle_opt}" Click="button_enter_Click">
                <Path Style="{StaticResource PathStyle_keyboard-return}" Fill="{StaticResource Color_light}" />
            </Button>
            <Button Grid.Row="3" Grid.Column="0" Style="{StaticResource ButtonStyle_opt}" Click="button_symbol_Click">
                <TextBlock Text="±" Style="{StaticResource TextBlockStyle_abc}" Foreground="{StaticResource Color_light}" />
            </Button>
            <Button Grid.Row="3" Grid.Column="1" Style="{StaticResource ButtonStyle_abc}" Click="button_0_Click">
                <TextBlock Text="0" Style="{StaticResource TextBlockStyle_abc}" />
            </Button>
            <Button Grid.Row="3" Grid.Column="2" Style="{StaticResource ButtonStyle_opt}" Click="button_pot_Click">
                <TextBlock Text="." Style="{StaticResource TextBlockStyle_abc}" Foreground="{StaticResource Color_light}"/>
            </Button>
        </Grid>

    </Grid>
</Window>