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