Define a GridSplitter and Horizontal Alignment Changed

   
  

<Window x:Class="GridSplitter_Example.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="GridSplitter Example">
<Grid>
  <Grid.ColumnDefinitions>
    <ColumnDefinition Name="Col0" />
    <ColumnDefinition Name="Col1" />
    <ColumnDefinition Name="Col2" />
    <ColumnDefinition Name="Col3" />
  </Grid.ColumnDefinitions>
  <Grid.RowDefinitions>
    <RowDefinition Name="Row0" />
    <RowDefinition Name="Row1" />
    <RowDefinition Name="Row2" />
  </Grid.RowDefinitions>

  <StackPanel Grid.Row="0" Grid.Column="0" Background="Orange">
    <TextBlock>Row 0 Col 0</TextBlock>
  </StackPanel>
  <StackPanel Grid.Row="1" Grid.Column="0" Background="Blue">
    <TextBlock>Row 1 Col 0</TextBlock>
  </StackPanel>
  <StackPanel Grid.Row="2" Grid.Column="0" Background="Green">
    <TextBlock>Row 2 Col 1</TextBlock>
  </StackPanel>
  <StackPanel Grid.Row="0" Grid.Column="1" Background="Purple">
    <TextBlock>Row 0 Col 1</TextBlock>
  </StackPanel>
  <StackPanel Grid.Row="1" Grid.Column="1" Background="Red">
    <TextBlock>Row 1 Col 1</TextBlock>
  </StackPanel>
  <StackPanel Grid.Row="2" Grid.Column="1" Background="Salmon">
   <TextBlock>Row 2 Col 1</TextBlock>
  </StackPanel>
  <StackPanel Grid.Row="0" Grid.Column="2" Background="MediumVioletRed">
    <TextBlock>Row 0 Col 2</TextBlock>
  </StackPanel>
  <StackPanel Grid.Row="1" Grid.Column="2" Background="SteelBlue">
    <TextBlock>Row 1 Col 2</TextBlock>
  </StackPanel>
  <StackPanel Grid.Row="2" Grid.Column="2" Background="Olive">
    <TextBlock>Row 2 Col 2</TextBlock>
  </StackPanel>
   
  <GridSplitter Name="myGridSplitter" Grid.Column="1" Grid.Row="1" Width="5"/>
  <StackPanel Grid.Column="3" Grid.RowSpan="3" Background="Brown">
  <TextBlock FontSize="14" Foreground="Yellow">Property Settings</TextBlock>
    <StackPanel>
      <TextBlock >HorizontalAlignment</TextBlock>
      <RadioButton Name="HorizontalAlignmentLeft" Checked="HorizontalAlignmentChanged" GroupName="HorizontalAlignmentProperty">
        Left
      </RadioButton>
      <RadioButton Name="HorizontalAlignmentRight" Checked="HorizontalAlignmentChanged" IsChecked="true" GroupName="HorizontalAlignmentProperty">
        Right (default)
      </RadioButton>
      <RadioButton Name="HorizontalAlignmentCenter" Checked="HorizontalAlignmentChanged" GroupName="HorizontalAlignmentProperty">
        Center
      </RadioButton>
      <RadioButton Name="HorizontalAlignmentStretch" Checked="HorizontalAlignmentChanged" GroupName="HorizontalAlignmentProperty">
        Stretch
      </RadioButton>
    </StackPanel>
  </StackPanel>
</Grid>
</Window>
//File:Window.xaml.cs
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Media;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace GridSplitter_Example
{
  public partial class Window1 : Window
  {
      public Window1()
      {
        InitializeComponent();
      }
      private void HorizontalAlignmentChanged(object sender, RoutedEventArgs e)
      {
          if ((Boolean)HorizontalAlignmentLeft.IsChecked)
            myGridSplitter.HorizontalAlignment = HorizontalAlignment.Left;
          else if ((Boolean)HorizontalAlignmentRight.IsChecked)
            myGridSplitter.HorizontalAlignment = HorizontalAlignment.Right;
          else if ((Boolean)HorizontalAlignmentCenter.IsChecked)
            myGridSplitter.HorizontalAlignment = HorizontalAlignment.Center;
          else if ((Boolean)HorizontalAlignmentStretch.IsChecked)
            myGridSplitter.HorizontalAlignment = HorizontalAlignment.Stretch;
      }
  }
}