c#1_12.xaml

 <Window x:Class="TicTacToe.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:TicTacToe"
         mc:Ignorable="d"
         ResizeMode="NoResize"
         Title="Tic Tac Toe" Height="600" Width="500">
     <Window.Resources>
  
         <Style TargetType="Label">
             <Setter Property="Background" Value="LightGray"/>
             <Setter Property="FontSize" Value="20" />
             <Setter Property="VerticalContentAlignment" Value="Center" />
         </Style>
  
         <Style TargetType="Button" x:Key="CellStyle">
             <Setter Property="Background" Value="White"/>
             <Setter Property="BorderThickness" Value="2"/>
             <Setter Property="BorderBrush" Value="DarkGray" />
             <Setter Property="FontSize" Value="65" />
         </Style>
  
         <Style TargetType="Button" x:Key="ButtonStyle">
             <Setter Property="Background" Value="PaleGreen"/>
             <Setter Property="FontSize" Value="20" />
         </Style>
  
     </Window.Resources>
     <Grid>
  
         <Grid.RowDefinitions>
             <RowDefinition Height="50" />
             <RowDefinition Height="*" />
             <RowDefinition Height="50" />
         </Grid.RowDefinitions>
  
         <Label Grid.Row="0" Name="GameInformation"></Label>
  
         <Grid Grid.Row="1">
  
             <Grid.ColumnDefinitions>
                 <ColumnDefinition Width="*" />
                 <ColumnDefinition Width="*" />
                 <ColumnDefinition Width="*" />
             </Grid.ColumnDefinitions>
  
             <Grid.RowDefinitions>
                 <RowDefinition Height="*" />
                 <RowDefinition Height="*" />
                 <RowDefinition Height="*" />
             </Grid.RowDefinitions>
  
             <Button Name="Button0_0" Grid.Column="0" Grid.Row="0" Style="{StaticResource CellStyle}" />
             <Button Name="Button0_1" Grid.Column="0" Grid.Row="1" Style="{StaticResource CellStyle}" />
             <Button Name="Button0_2" Grid.Column="0" Grid.Row="2" Style="{StaticResource CellStyle}" />
  
             <Button Name="Button1_0" Grid.Column="1" Grid.Row="0" Style="{StaticResource CellStyle}" />
             <Button Name="Button1_1" Grid.Column="1" Grid.Row="1" Style="{StaticResource CellStyle}" />
             <Button Name="Button1_2" Grid.Column="1" Grid.Row="2" Style="{StaticResource CellStyle}" />
  
             <Button Name="Button2_0" Grid.Column="2" Grid.Row="0" Style="{StaticResource CellStyle}" />
             <Button Name="Button2_1" Grid.Column="2" Grid.Row="1" Style="{StaticResource CellStyle}" />
             <Button Name="Button2_2" Grid.Column="2" Grid.Row="2" Style="{StaticResource CellStyle}" />
         </Grid>
  
         <Button ="StartButton" Grid.Row="2" Style="{StaticResource ButtonStyle}">
             Neues Spiel starten
         </Button>
  
     </Grid>
  
 </Window>