<Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" x:Class="ElemCollMethods.Pane1" WindowTitle="UI Element Collection Methods Sample"> <StackPanel> <TextBlock Name="txt" FontSize="16">UI Element Collection - Methods</TextBlock> <TabControl> <TabItem MouseLeftButtonUp="GetCount"> <TabItem.Header>UIElement Count</TabItem.Header> </TabItem> </TabControl> <StackPanel Name="sp1"></StackPanel> </StackPanel> </Page> //File:Window.xaml.cs using System; using System.Windows; using System.Windows.Controls; using System.Windows.Documents; using System.Windows.Navigation; using System.Windows.Shapes; using System.Windows.Data; using System.Windows.Input; namespace ElemCollMethods { public partial class Pane1 : Page { System.Windows.Controls.Button btn, btn1, btn2, btn3; void GetCount(object sender, RoutedEventArgs e) { TextBlock txt3 = new TextBlock(); sp1.Children.Add(txt3); txt3.Text = "UIElement Count is equal to " + sp1.Children.Count.ToString(); } } }