Hi
I'm new in WPF so I try to create a WPF UserControl. My problem is about the style of the user control I've Created. On a design time I got this error message
Can only base on a Style with target type that is base type 'RichTextBox'.
  at System.Windows.Style.Seal() at
  System.Windows.StyleHelper.UpdateStyleCache(FrameworkElement
  fe, FrameworkContentElement fce, Style
  oldStyle, Style newStyle, Style&
  styleCache) at
  System.Windows.FrameworkElement.OnStyleChanged(DependencyObject
  d, DependencyPropertyChangedEventArgs
  e) at
  System.Windows.DependencyObject.OnPropertyChanged(DependencyPropertyChangedEventArgs
  e) at
  System.Windows.FrameworkElement.OnPropertyChanged(DependencyPropertyChangedEventArgs
  e) at
  System.Windows.DependencyObject.NotifyPropertyChange(DependencyPropertyChangedEventArgs
  args) at
  System.Windows.DependencyObject.UpdateEffectiveValue(EntryIndex
  entryIndex, DependencyProperty dp,
  PropertyMetadata metadata,
  EffectiveValueEntry oldEntry,
  EffectiveValueEntry& newEntry, Boolean
  coerceWithDeferredReference,
  OperationType operationType) at
  System.Windows.DependencyObject.InvalidateProperty(DependencyProperty
  dp) at
  System.Windows.FrameworkElement.UpdateStyleProperty()
  at
  System.Windows.TreeWalkHelper.InvalidateStyleAndReferences(DependencyObject
  d, ResourcesChangeInfo info, Boolean
  containsTypeOfKey) at
  System.Windows.TreeWalkHelper.OnResourcesChanged(DependencyObject
  d, ResourcesChangeInfo info, Boolean
  raiseResourceChangedEvent) at
  System.Windows.TreeWalkHelper.OnResourcesChangedCallback(DependencyObject
  d, ResourcesChangeInfo info) at
  System.Windows.DescendentsWalker1._VisitNode(DependencyObject
  d) at
  System.Windows.DescendentsWalker1.VisitNode(FrameworkElement
  fe) at
  System.Windows.DescendentsWalker1.VisitNode(DependencyObject
  d) at
  System.Windows.DescendentsWalker1.WalkLogicalChildren(FrameworkElement feParent, FrameworkContentElement
  fceParent, IEnumerator
  logicalChildren) at
  System.Windows.DescendentsWalker1.WalkFrameworkElementLogicalThenVisualChildren(FrameworkElement
  feParent, Boolean hasLogicalChildren)
  at
  System.Windows.DescendentsWalker1.IterateChildren(DependencyObject
  d) at
  System.Windows.DescendentsWalker1._VisitNode(DependencyObject
  d) at
  System.Windows.DescendentsWalker1.VisitNode(FrameworkElement
  fe) at
  System.Windows.DescendentsWalker1.VisitNode(DependencyObject
  d) at
  System.Windows.DescendentsWalker1.WalkLogicalChildren(FrameworkElement feParent, FrameworkContentElement
  fceParent, IEnumerator
  logicalChildren) at
  System.Windows.DescendentsWalker1.WalkFrameworkElementLogicalThenVisualChildren(FrameworkElement
  feParent, Boolean hasLogicalChildren)
  at
  System.Windows.DescendentsWalker1.IterateChildren(DependencyObject
  d) at
  System.Windows.DescendentsWalker1._VisitNode(DependencyObject
  d) at
  System.Windows.DescendentsWalker1.VisitNode(FrameworkElement
  fe) at
  System.Windows.DescendentsWalker1.VisitNode(DependencyObject
  d) at
  System.Windows.DescendentsWalker1.WalkLogicalChildren(FrameworkElement feParent, FrameworkContentElement
  fceParent, IEnumerator
  logicalChildren) at
  System.Windows.DescendentsWalker1.WalkFrameworkElementLogicalThenVisualChildren(FrameworkElement
  feParent, Boolean hasLogicalChildren)
  at
  System.Windows.DescendentsWalker1.IterateChildren(DependencyObject
  d) at
  System.Windows.DescendentsWalker1._VisitNode(DependencyObject
  d) at
  System.Windows.DescendentsWalker1.VisitNode(FrameworkElement
  fe) at
  System.Windows.DescendentsWalker1.VisitNode(DependencyObject
  d) at
  System.Windows.DescendentsWalker1.WalkLogicalChildren(FrameworkElement feParent, FrameworkContentElement
  fceParent, IEnumerator
  logicalChildren) at
  System.Windows.DescendentsWalker1.WalkFrameworkElementLogicalThenVisualChildren(FrameworkElement
  feParent, Boolean hasLogicalChildren)
  at
  System.Windows.DescendentsWalker1.IterateChildren(DependencyObject
  d) at
  System.Windows.DescendentsWalker1._VisitNode(DependencyObject
  d) at
  System.Windows.DescendentsWalker1.VisitNode(FrameworkElement
  fe) at
  System.Windows.DescendentsWalker1.VisitNode(DependencyObject
  d) at
  System.Windows.DescendentsWalker1.WalkLogicalChildren(FrameworkElement feParent, FrameworkContentElement
  fceParent, IEnumerator
  logicalChildren) at
  System.Windows.DescendentsWalker1.WalkFrameworkElementLogicalThenVisualChildren(FrameworkElement
  feParent, Boolean hasLogicalChildren)
  at
  System.Windows.DescendentsWalker1.IterateChildren(DependencyObject
  d) at
  System.Windows.DescendentsWalker1._VisitNode(DependencyObject
  d) at
  System.Windows.DescendentsWalker1.VisitNode(FrameworkElement
  fe) at
  System.Windows.DescendentsWalker1.VisitNode(DependencyObject
  d) at
  System.Windows.DescendentsWalker1.WalkLogicalChildren(FrameworkElement feParent, FrameworkContentElement
  fceParent, IEnumerator
  logicalChildren) at
  System.Windows.DescendentsWalker1.WalkFrameworkElementLogicalThenVisualChildren(FrameworkElement
  feParent, Boolean hasLogicalChildren)
  at
  System.Windows.DescendentsWalker1.IterateChildren(DependencyObject
  d) at
  System.Windows.DescendentsWalker1._VisitNode(DependencyObject
  d) at
  System.Windows.DescendentsWalker1.VisitNode(FrameworkElement
  fe) at
  System.Windows.DescendentsWalker1.VisitNode(DependencyObject
  d) at
  System.Windows.DescendentsWalker1.WalkLogicalChildren(FrameworkElement feParent, FrameworkContentElement
  fceParent, IEnumerator
  logicalChildren) at
  System.Windows.DescendentsWalker1.WalkFrameworkElementLogicalThenVisualChildren(FrameworkElement
  feParent, Boolean hasLogicalChildren)
  at
  System.Windows.DescendentsWalker1.IterateChildren(DependencyObject
  d) at
  System.Windows.DescendentsWalker1._VisitNode(DependencyObject
  d) at
  System.Windows.DescendentsWalker1.VisitNode(FrameworkElement
  fe) at
  System.Windows.DescendentsWalker1.VisitNode(DependencyObject
  d) at
  System.Windows.DescendentsWalker1.WalkLogicalChildren(FrameworkElement feParent, FrameworkContentElement
  fceParent, IEnumerator
  logicalChildren) at
  System.Windows.DescendentsWalker1.WalkFrameworkElementLogicalThenVisualChildren(FrameworkElement
  feParent, Boolean hasLogicalChildren)
  at
  System.Windows.DescendentsWalker1.IterateChildren(DependencyObject
  d) at
  System.Windows.DescendentsWalker1._VisitNode(DependencyObject
  d) at
  System.Windows.DescendentsWalker1.VisitNode(FrameworkElement
  fe) at
  System.Windows.DescendentsWalker1.VisitNode(DependencyObject
  d) at
  System.Windows.DescendentsWalker1.WalkLogicalChildren(FrameworkElement feParent, FrameworkContentElement
  fceParent, IEnumerator
  logicalChildren) at
  System.Windows.DescendentsWalker1.WalkFrameworkElementLogicalThenVisualChildren(FrameworkElement
  feParent, Boolean hasLogicalChildren)
  at
  System.Windows.DescendentsWalker1.IterateChildren(DependencyObject
  d) at
  System.Windows.DescendentsWalker`1.StartWalk(DependencyObject
  startNode, Boolean skipStartNode) at
  System.Windows.TreeWalkHelper.InvalidateOnResourcesChange(FrameworkElement
  fe, FrameworkContentElement fce,
  ResourcesChangeInfo info) at
  System.Windows.ResourceDictionary.NotifyOwners(ResourcesChangeInfo
  info) at
  System.Windows.ResourceDictionary.EndInit()
  at
  MS.Internal.Host.Designer.OnAppResourcesChanged(Object
  sender, EventArgs e) at
  MS.Internal.Host.Designer.get_View()
  at
  MS.Internal.Designer.VSDesigner.Load()
  at
  MS.Internal.Designer.VSIsolatedDesigner.VSIsolatedView.Load()
  at
  MS.Internal.Designer.VSIsolatedDesigner.VSIsolatedDesignerFactory.Load(IsolatedView
  view) at
  MS.Internal.Host.Isolation.IsolatedDesigner.BootstrapProxy.LoadDesigner(IsolatedDesignerFactory
  factory, IsolatedView view) at
  MS.Internal.Host.Isolation.IsolatedDesigner.BootstrapProxy.LoadDesigner(IsolatedDesignerFactory
  factory, IsolatedView view) at
  MS.Internal.Host.Isolation.IsolatedDesigner.Load()
  at
  MS.Internal.Designer.DesignerPane.LoadDesignerView()
And at a run time An error Message type XamlParseException Occurs and the message is:
  Cannot create instance of 'RichTextBox' defined in assembly 'PresentationFramework, 
  Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'. Can only base on a 
  Style with target type that is base type 'RichTextBox'. Error at object 
  'System.Windows.Controls.Grid' in markup file 'NameSpace;component/usercontrols
  /myusercontrol.xaml' Line 125 Position 14.
My user control have 3 richtextboxes 1 textbox and 3 dropdownlist and about 10 buttons. I think The problem is about to define the style of my user control, can anyone help me to do this.
Thanks