Change the Visibility property of a UIElement.

   
   

<Window xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    x:Class="Visibility_Layout_Samp.Window1"
    Title="UIELement.Visibility Sample">
      <DockPanel>
            <StackPanel DockPanel.Dock="Left">
                <Button Name="btn1" Height="25" Click="contentVis">Visibility="Visible"</Button>
                <Button Name="btn2" Height="25" Click="contentHid">Visibility="Hidden"</Button>
                <Button Name="btn3" Height="25" Click="contentCol">Visibility="Collapsed"</Button> 
            </StackPanel>    
            <StackPanel HorizontalAlignment="Center">
                <TextBox Name="tb1" Width="100" Height="50">A TextBox</TextBox>
                <TextBlock Name="txt1" TextWrapping="Wrap" FontSize="14"/>
            </StackPanel>
        </DockPanel>
</Window>

//File:Window.xaml.cs
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;

namespace Visibility_Layout_Samp
{
  public partial class Window1 : Window
  {
        public void contentVis(object sender, RoutedEventArgs e)
        {
            tb1.Visibility = System.Windows.Visibility.Visible;
            txt1.Text = "Visibility is now set to Visible.";
        }

        public void contentHid(object sender, RoutedEventArgs e)
        {
            tb1.Visibility = System.Windows.Visibility.Hidden;
            txt1.Text = "Visibility is now set to Hidden.";
        }

        public void contentCol(object sender, RoutedEventArgs e)
        {
            tb1.Visibility = System.Windows.Visibility.Collapsed;
            txt1.Text = "Visibility is now set to Collapsed.";
        }
    }
}