WPF

<Expander Grid.Column="3" Grid.RowSpan="2" Header="expander1" Margin="3,12,-83,18" Name="expander1" BorderBrush="Red" BorderThickness="2" Width="200" Height="400">
     <StackPanel>
       <Button Width="100">This is the button one</Button>
       <Button Width="100">This is the button two</Button>
       </StackPanel>

     <Expander.Triggers>
       <EventTrigger RoutedEvent="Expander.Expanded">
         <BeginStoryboard>
           <Storyboard>
             <DoubleAnimation Storyboard.TargetName="expander1" Storyboard.TargetProperty="Width"
                              From="0" To="200" Duration="0:0:0.25" />
             <DoubleAnimation Storyboard.TargetName="expander1" Storyboard.TargetProperty="Height"
                              From="0" To="400" Duration="0:0:0.25" />
           </Storyboard>
         </BeginStoryboard>
       </EventTrigger>
     </Expander.Triggers>
   </Expander>

<Window 
        x:Class="WPFAppl.WpfWindow" 
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 	
        xmlns:local="clr-namespace:WPFAppl" 
        Title="Title"  
        Height="200"  
        Width="400"          
        WindowStartupLocation="CenterScreen"  
        Name="This"          
        Loaded="UserControl_Loaded">
    <window.resources>
        <datatemplate x:key="ThisTemplate"> 
           <grid> 
                <grid.rowdefinitions> 
                    <rowdefinition height="*" /> 
                </grid.rowdefinitions> 
                <stackpanel orientation="Horizontal">
                            Grid.Row="0"> 
                    <windowsformshost width="360">
                                      xmlns="clr-namespace:System.Windows.Forms.Integration;assembly=WindowsFormsIntegration"> 
                        <datagridview x:name="gridView"> 
                                      AllowUserToAddRows="False" 
                                      SelectionMode="FullRowSelect" 
                                      EditMode="EditProgrammatically" 
                                      xmlns="clr-namespace:System.Windows.Forms;assembly=System.Windows.Forms">
                        </datagridview >
                    </windowsformshost > 
                </stackpanel> 
            </grid> 
        </datatemplate > 
    </window.resources > 
</window >

using System;    
using System.Collections.Generic;    
using System.Linq;   
using System.Text;   
using System.Windows;    
using System.Windows.Controls;   
using System.Windows.Data;   
using System.Windows.Documents;      
using System.Windows.Input;      
using System.Windows.Media;      
using System.Windows.Media.Imaging;      
using System.Windows.Navigation;     
using System.Windows.Shapes;     
using System.ComponentModel;     
using System.Collections.ObjectModel;    
using System.Xml;    
using System.Data;   
using System.Globalization; 
using System.Windows.Threading; 
using System.Threading; 
 
namespace WPFAppl 
{       /// <summary>        
    /// Interaction logic for Window1.xaml       
    /// </summary>       
    public partial class WpfWindow : Window 
    { 
        public WpfWindow()  
        {  
            InitializeComponent();  
        } 
 
        private DataTemplate ChildTemplate; 
        private ContentPresenter ParentTemplate; 
        private DataTable dt; 
 
        private void UserControl_Loaded(object sender, RoutedEventArgs e) 
        { 
            this.ContentTemplate = FindResource("ThisTemplate") as DataTemplate; 
            ChildTemplate = FindResource("ThisTemplate") as DataTemplate; 
            ParentTemplate = FindVisualChild<contentpresenter>(This); 
            dt = new DataTable(); 
            dt.Columns.Add("attr1", typeof(string)); 
            dt.Columns.Add("attr2", typeof(string)); 
            dt.Columns.Add("attr3", typeof(string)); 
            System.Windows.Forms.DataGridView gw1 = ChildTemplate.FindName("gridView", ParentTemplate) as System.Windows.Forms.DataGridView; 
            gw1.DataSource = dt; 
        } 
 
        //find element in visual tree 
        private childItem FindVisualChild<childitem>(DependencyObject obj) where childItem : DependencyObject 
        { 
            for (int i = 0; i < VisualTreeHelper.GetChildrenCount(obj); i++) 
            { 
                DependencyObject child = VisualTreeHelper.GetChild(obj, i); 
                if (child != null && child is childItem) 
                    return (childItem)child; 
                else 
                { 
                    childItem childOfChild = FindVisualChild<childitem>(child); 
                    if (childOfChild != null) 
                        return childOfChild; 
                } 
            } 
            return null; 
        } 
    } 
}  </childitem></childitem></contentpresenter>