Performance UserControl / CustomControl - wpf

Question

I already searched a lot of sites on the net, but didn't find any solution. The statement is, that there is no performance difference between a UserControl and a CustomControl.
But I have the following test class X, UserControl, CustomControl and MainWindow:
public class X : INotifyPropertyChanged
{
private string _title;
public string Title
{
get
{
return _title;
}
set
{
if (value == _title)
{
return;
}
_title = value;
OnPropertyChanged("Title");
}
}
public event PropertyChangedEventHandler PropertyChanged;
[NotifyPropertyChangedInvocator]
protected virtual void OnPropertyChanged(string propertyName)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
{
handler(this, new PropertyChangedEventArgs(propertyName));
}
}
}
UserControl:
<UserControl x:Class="controlperformance.DisplayView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006">
<Grid Name="root" Background="LightGray">
<TextBlock Text="{Binding Title}" />
</Grid>
</UserControl>
CustomControl:
public class DisplayControl : Control
{
#region Title
public string Title
{
get
{
return (string)GetValue(TitleProperty);
}
set
{
SetValue(TitleProperty, value);
}
}
public static readonly DependencyProperty TitleProperty = DependencyProperty.Register("Title",
typeof(string),
typeof(DisplayControl),
new PropertyMetadata(default(string)));
#endregion
static DisplayControl()
{
DefaultStyleKeyProperty.OverrideMetadata(typeof(DisplayControl), new FrameworkPropertyMetadata(typeof(DisplayControl)));
}
}
Xaml:
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type local:DisplayControl}">
<Grid Background="white">
<TextBlock Text="{TemplateBinding Title}" />
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
MainWindow:
public partial class MainWindow : Window
{
Stopwatch sw = new Stopwatch();
public MainWindow()
{
InitializeComponent();
Loaded += OnLoaded;
sw.Start();
ObservableCollection<X> list = new ObservableCollection<X>();
Random r = new Random();
for (int i = 0; i < 50000; i++)
{
list.Add(new X { Title = r.Next().ToString()});
}
itemscontrol.ItemsSource = list;
}
private void OnLoaded(object sender, RoutedEventArgs routedEventArgs)
{
sw.Stop();
MessageBox.Show(sw.Elapsed.ToString());
}
}
MainWindow Content:
<ItemsControl Name="itemscontrol">
<ItemsControl.ItemTemplate>
<!--<DataTemplate DataType="{x:Type Controlperformance:X}">
<Controlperformance:DisplayView DataContext="{Binding}" />
</DataTemplate>-->
<DataTemplate DataType="{x:Type Controlperformance:X}">
<Controlperformance:DisplayControl Title="{Binding Title}"/>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
When using the CustomControl, the MessageBox shows approx. 20 Seconds on my computer, but when using the UserControl, it takes about a minute! Replacing the Control with its Grid an TextBox, it is even faster than the CustomControl (~16 sec).
Can someone see where the bottleneck is? The problem raises in my real-world application, where the Template/Control would be much more complex.
Thanks a lot,
micro

Answer 1

This is a late answer but the basic difference is that a User Control is almost like a window in that you have the the control itself and then other controls like, buttons, grids, textboxes, etc can be added to it. The basic difference between a window and User Control is that the User Control can and must be displayed within a window.
A Custom Control on the other hand is just a control, it can be used to create a control with a specific functionality for which there are no built in controls or to give an existing control, like buttons, textboxes, etc a specific style to match the theme of your application. You can also add in extra features to existing controls by using a custom control such as adding a label to a text box to show it's purpose.
The difference in loading time is essentially a reflection of the different purposes of User and Custom Controls, with a User Control it load the control and the elements within that control so the loading time may be longer. With a Custom Control only the control itself must load so the so it won't take any longer to load than most built in WPF controls i.e. a button Custom Control shouldn't take longer than a built in button control.