Use a ContentTemplate and determine whether the control contains content
//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.Media;
using System.Collections.ObjectModel;
namespace ContentControlSimple
{
public partial class Page1 : Canvas
{
void OnClick(object sender, RoutedEventArgs e)
{
if (contCtrl.HasContent == true)
{
MessageBox.Show("contCtrl has content");
}
}
}
}