fixed all OnApplyTemplate overrides that hook into events.

ExtendedWPFToolkitSolution/Src/WPFToolkit.Extended/Calculator/Implementation/Calculator.cs

@@ -199,7 +199,7 @@ namespace Microsoft.Windows.Controls
         {
             base.OnApplyTemplate();
 
-            _buttonPanel = (ContentControl)GetTemplateChild("PART_CalculatorButtonPanel");
+            _buttonPanel = GetTemplateChild("PART_CalculatorButtonPanel") as ContentControl;
         }
 
         protected override void OnTextInput(TextCompositionEventArgs e)

ExtendedWPFToolkitSolution/Src/WPFToolkit.Extended/CalculatorUpDown/Implementation/CalculatorUpDown.cs

@@ -105,10 +105,16 @@ namespace Microsoft.Windows.Controls
         public override void OnApplyTemplate()
         {
             base.OnApplyTemplate();
-            _calculatorPopup = (Popup)GetTemplateChild("PART_CalculatorPopup");
-            _calculatorPopup.Opened += CalculatorPopup_Opened;
 
-            _calculator = (Calculator)GetTemplateChild("PART_Calculator");
+            if (_calculatorPopup != null)
+                _calculatorPopup.Opened -= CalculatorPopup_Opened;
+
+            _calculatorPopup = GetTemplateChild("PART_CalculatorPopup") as Popup;
+
+            if (_calculatorPopup != null)
+                _calculatorPopup.Opened += CalculatorPopup_Opened;
+
+            _calculator = GetTemplateChild("PART_Calculator") as Calculator;
         }
 
         #endregion //Base Class Overrides

ExtendedWPFToolkitSolution/Src/WPFToolkit.Extended/ChildWindow/Implementation/ChildWindow.cs

@@ -395,7 +395,15 @@ namespace Microsoft.Windows.Controls
         {
             base.OnApplyTemplate();
 
-            _dragWidget = (Border)GetTemplateChild("PART_DragWidget");
+            if (_dragWidget != null)
+            {
+                _dragWidget.RemoveHandler(UIElement.MouseLeftButtonDownEvent, new MouseButtonEventHandler(HeaderLeftMouseButtonDown));
+                _dragWidget.RemoveHandler(UIElement.MouseLeftButtonUpEvent, new MouseButtonEventHandler(HeaderMouseLeftButtonUp));
+                _dragWidget.MouseMove -= (o, e) => HeaderMouseMove(e);
+            }
+
+            _dragWidget = GetTemplateChild("PART_DragWidget") as Border;
+
             if (_dragWidget != null)
             {
                 _dragWidget.AddHandler(UIElement.MouseLeftButtonDownEvent, new MouseButtonEventHandler(HeaderLeftMouseButtonDown), true);
@@ -403,7 +411,11 @@ namespace Microsoft.Windows.Controls
                 _dragWidget.MouseMove += (o, e) => HeaderMouseMove(e);
             }
 
-            CloseButton = (Button)GetTemplateChild("PART_CloseButton");
+            if (CloseButton != null)
+                CloseButton.Click -= (o, e) => Close();
+
+            CloseButton = GetTemplateChild("PART_CloseButton") as Button;
+
             if (CloseButton != null)
                 CloseButton.Click += (o, e) => Close();
 

ExtendedWPFToolkitSolution/Src/WPFToolkit.Extended/ColorCanvas/Implementation/ColorCanvas.cs

@@ -202,7 +202,8 @@ namespace Microsoft.Windows.Controls
                 _colorShadingCanvas.SizeChanged -= ColorShadingCanvas_SizeChanged;
             }
 
-            _colorShadingCanvas = (Canvas)GetTemplateChild("PART_ColorShadingCanvas");
+            _colorShadingCanvas = GetTemplateChild("PART_ColorShadingCanvas") as Canvas;
+
             if (_colorShadingCanvas != null)
             {
                 _colorShadingCanvas.MouseLeftButtonDown += ColorShadingCanvas_MouseLeftButtonDown;
@@ -211,14 +212,16 @@ namespace Microsoft.Windows.Controls
                 _colorShadingCanvas.SizeChanged += ColorShadingCanvas_SizeChanged;
             }
 
-            _colorShadeSelector = (Canvas)GetTemplateChild("PART_ColorShadeSelector");
+            _colorShadeSelector = GetTemplateChild("PART_ColorShadeSelector") as Canvas;
+
             if (_colorShadeSelector != null)
                 _colorShadeSelector.RenderTransform = _colorShadeSelectorTransform;
 
             if (_spectrumSlider != null)
                 _spectrumSlider.ValueChanged -= SpectrumSlider_ValueChanged;
             
-            _spectrumSlider = (ColorSpectrumSlider)GetTemplateChild("PART_SpectrumSlider");
+            _spectrumSlider = GetTemplateChild("PART_SpectrumSlider") as ColorSpectrumSlider;
+
             if (_spectrumSlider != null)
                 _spectrumSlider.ValueChanged += SpectrumSlider_ValueChanged;            
 

ExtendedWPFToolkitSolution/Src/WPFToolkit.Extended/ColorPicker/Implementation/ColorPicker.cs

@@ -228,21 +228,21 @@ namespace Microsoft.Windows.Controls
             if (_availableColors != null)
                 _availableColors.SelectionChanged -= Color_SelectionChanged;
 
-            _availableColors = (ListBox)GetTemplateChild("PART_AvailableColors");
+            _availableColors = GetTemplateChild("PART_AvailableColors") as ListBox;
             if (_availableColors != null)
                 _availableColors.SelectionChanged += Color_SelectionChanged;
 
             if (_standardColors != null)
                 _standardColors.SelectionChanged -= Color_SelectionChanged;
 
-            _standardColors = (ListBox)GetTemplateChild("PART_StandardColors");
+            _standardColors = GetTemplateChild("PART_StandardColors") as ListBox;
             if (_standardColors != null)
                 _standardColors.SelectionChanged += Color_SelectionChanged;
 
             if (_recentColors != null)
                 _recentColors.SelectionChanged -= Color_SelectionChanged;
 
-            _recentColors = (ListBox)GetTemplateChild("PART_RecentColors");
+            _recentColors = GetTemplateChild("PART_RecentColors") as ListBox;
             if (_recentColors != null)
                 _recentColors.SelectionChanged += Color_SelectionChanged;
         }

ExtendedWPFToolkitSolution/Src/WPFToolkit.Extended/Core/Primitives/UpDownBase.cs

@@ -51,7 +51,7 @@ namespace Microsoft.Windows.Controls.Primitives
         {
             get { return (bool)GetValue(MouseWheelActiveOnFocusProperty); }
             set { SetValue(MouseWheelActiveOnFocusProperty, value); }
-        }        
+        }
 
         #endregion //MouseWheelActiveOnFocus
 
@@ -120,8 +120,14 @@ namespace Microsoft.Windows.Controls.Primitives
             base.OnApplyTemplate();
 
             TextBox = GetTemplateChild(ElementTextName) as TextBox;
+
+            if (Spinner != null)
+                Spinner.Spin -= OnSpinnerSpin;
+
             Spinner = GetTemplateChild(ElementSpinnerName) as Spinner;
-            Spinner.Spin += OnSpinnerSpin;
+
+            if (Spinner != null)
+                Spinner.Spin += OnSpinnerSpin;
 
             SetValidSpinDirection();
         }

ExtendedWPFToolkitSolution/Src/WPFToolkit.Extended/DateTimePicker/Implementation/DateTimePicker.cs

@@ -38,7 +38,7 @@ namespace Microsoft.Windows.Controls
         {
             get { return (TimeFormat)GetValue(TimeFormatProperty); }
             set { SetValue(TimeFormatProperty, value); }
-        }        
+        }
 
         #endregion //TimeFormat
 
@@ -98,10 +98,19 @@ namespace Microsoft.Windows.Controls
         {
             base.OnApplyTemplate();
 
-            _calendar = (Calendar)GetTemplateChild("Part_Calendar");
-            _calendar.SelectedDatesChanged += Calendar_SelectedDatesChanged;
-            _calendar.SelectedDate = Value ?? null;
-            _calendar.DisplayDate = Value ?? DateTime.Now;
+            if (_calendar != null)
+            {
+                _calendar.SelectedDatesChanged -= Calendar_SelectedDatesChanged;
+            }
+
+            _calendar = GetTemplateChild("Part_Calendar") as Calendar;
+
+            if (_calendar != null)
+            {
+                _calendar.SelectedDatesChanged += Calendar_SelectedDatesChanged;
+                _calendar.SelectedDate = Value ?? null;
+                _calendar.DisplayDate = Value ?? DateTime.Now;
+            }
         }
 
         protected override void OnPreviewMouseUp(MouseButtonEventArgs e)

ExtendedWPFToolkitSolution/Src/WPFToolkit.Extended/DateTimeUpDown/Implementation/DateTimeUpDown.cs

@@ -115,8 +115,13 @@ namespace Microsoft.Windows.Controls
 
         public override void OnApplyTemplate()
         {
+            if (TextBox != null)
+                TextBox.SelectionChanged -= TextBox_SelectionChanged;
+
             base.OnApplyTemplate();
-            TextBox.SelectionChanged += TextBox_SelectionChanged;
+
+            if (TextBox != null)
+                TextBox.SelectionChanged += TextBox_SelectionChanged;
         }
 
         protected override void OnCultureInfoChanged(CultureInfo oldValue, CultureInfo newValue)
@@ -202,7 +207,7 @@ namespace Microsoft.Windows.Controls
         protected override string ConvertValueToText()
         {
             if (Value == null) return string.Empty;
-            
+
             return Value.Value.ToString(GetFormatString(Format), CultureInfo);
         }
 

ExtendedWPFToolkitSolution/Src/WPFToolkit.Extended/MaskedTextBox/Implementation/MaskedTextBox.cs

@@ -205,6 +205,15 @@ namespace Microsoft.Windows.Controls
             TextProperty.OverrideMetadata(typeof(MaskedTextBox), new FrameworkPropertyMetadata(OnTextChanged));
         }
 
+        public MaskedTextBox()
+        {
+            PreviewTextInput += TextBox_PreviewTextInput;
+            PreviewKeyDown += TextBox_PreviewKeyDown;
+
+            CommandBindings.Add(new CommandBinding(ApplicationCommands.Paste, Paste)); //handle paste
+            CommandBindings.Add(new CommandBinding(ApplicationCommands.Cut, null, CanCut)); //surpress cut
+        }
+
         #endregion //Constructors
 
         #region Base Class Overrides
@@ -213,12 +222,6 @@ namespace Microsoft.Windows.Controls
         {
             base.OnApplyTemplate();
 
-            PreviewTextInput += TextBox_PreviewTextInput;
-            PreviewKeyDown += TextBox_PreviewKeyDown;
-
-            CommandBindings.Add(new CommandBinding(ApplicationCommands.Paste, Paste)); //handle paste
-            CommandBindings.Add(new CommandBinding(ApplicationCommands.Cut, null, CanCut)); //surpress cut
-
             UpdateText(MaskProvider, 0);
         }
 

ExtendedWPFToolkitSolution/Src/WPFToolkit.Extended/MessageBox/Implementation/MessageBox.cs

@@ -39,7 +39,10 @@ namespace Microsoft.Windows.Controls
         }
 
         internal MessageBox()
-        { /*user cannot create instance */ }
+        { 
+            /*user cannot create instance */
+            AddHandler(ButtonBase.ClickEvent, new RoutedEventHandler(Button_Click));
+        }
 
         #endregion //Constructors
 
@@ -156,12 +159,14 @@ namespace Microsoft.Windows.Controls
         {
             base.OnApplyTemplate();
 
+            if (DragWidget != null)
+                DragWidget.DragDelta -= (o, e) => ProcessMove(e);
+
             DragWidget = GetTemplateChild("PART_DragWidget") as Thumb;
+
             if (DragWidget != null)
                 DragWidget.DragDelta += (o, e) => ProcessMove(e);
 
-            AddHandler(ButtonBase.ClickEvent, new RoutedEventHandler(Button_Click));
-
             ChangeVisualState(_button.ToString(), true);
 
             SetDefaultResult();

ExtendedWPFToolkitSolution/Src/WPFToolkit.Extended/MultiLineTextEditor/Implementation/MultiLineTextEditor.cs

@@ -124,11 +124,11 @@ namespace Microsoft.Windows.Controls
 
             if (_resizeThumb != null)
                 _resizeThumb.DragDelta -= ResizeThumb_DragDelta;
-            _resizeThumb = (Thumb)GetTemplateChild("PART_ResizeThumb");
+
+            _resizeThumb = GetTemplateChild("PART_ResizeThumb") as Thumb;
 
             if (_resizeThumb != null)
                 _resizeThumb.DragDelta += ResizeThumb_DragDelta;
-
         }
 
         #endregion //Bass Class Overrides

ExtendedWPFToolkitSolution/Src/WPFToolkit.Extended/TimePicker/Implementation/TimePicker.cs

@@ -317,9 +317,16 @@ namespace Microsoft.Windows.Controls
         {
             base.OnApplyTemplate();
 
-            _timeListBox = (ListBox)GetTemplateChild("PART_TimeListItems");
-            _timeListBox.ItemsSource = GenerateTimeListItemsSource();
-            _timeListBox.SelectionChanged += TimeListBox_SelectionChanged;
+            if (_timeListBox != null)
+                _timeListBox.SelectionChanged -= TimeListBox_SelectionChanged;
+
+            _timeListBox = GetTemplateChild("PART_TimeListItems") as ListBox;
+
+            if (_timeListBox != null)
+            {
+                _timeListBox.SelectionChanged += TimeListBox_SelectionChanged;
+                _timeListBox.ItemsSource = GenerateTimeListItemsSource();
+            }
         }
 
         #endregion //Base Class Overrides