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class library inheritance

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This is a migrated thread and some comments may be shown as answers.
David Ocasio
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David Ocasio asked on 03 Mar 2011, 04:19 PM
i like to create dialogs by inheriting a radwindow.
<telerik:RadWindow x:Class="agClassLibrary.TraceWindow"
    MinWidth="400" MinHeight="250"
    mc:Ignorable="d" d:DesignHeight="250" d:DesignWidth="400">
    <Grid x:Name="LayoutRoot" Background="White">
        <ListBox Name="lbMessage" >
Imports System.Windows.Data
Imports Telerik.Windows.Controls
Imports System.ComponentModel
Imports System.ComponentModel.DataAnnotations
Imports System.Collections.ObjectModel
Imports agClassLibrary
Imports System.Linq
Imports System.ServiceModel.DomainServices.Client
Imports System.Runtime.CompilerServices
Partial Public Class TraceWindow
    Inherits RadWindow
    Protected lstMessages As New ObservableCollection(Of String)
    <Display(Name:="MaxMessages", Description:="MaxMessages")> _
    Public Property MaxMessages() As Integer
            Return _MaxMessages
        End Get
        Set(ByVal value As Integer)
            _MaxMessages = value
        End Set
    End Property
    Protected _MaxMessages As Integer = 500
    Public Sub New()
        lbMessage.ItemsSource = lstMessages
    End Sub
    Protected Sub AddMessage(ByVal message As String)
        Dim TraceMessage As String = Now & " --> " & message
    End Sub
    Public Sub Trace(ByVal EntitySet As EntitySet)
        Trace(EntitySet.EntityType.ToString & ":" & EntitySet.Count)
    End Sub
    Public Sub Trace(ByVal message As String)
        If lbMessage.Items.Count > MaxMessages Then
        End If
        lbMessage.ScrollIntoView(lbMessage.Items(lbMessage.Items.Count - 1))
    End Sub
End Class

This works fine if it is in the main silverlight project
but if it is placed in a silverlight class library the Visual Studio Designer errs out.

An unhandled exception was encountered while trying to render the current silverlight project on the design surface. To diagnose this failure, please try to run the project in a regular browser using the silverlight developer runtime.
   at Microsoft.Windows.Design.Platform.SilverlightViewProducer.OnUnhandledException(Object sender, ViewUnhandledExceptionEventArgs e)
   at Microsoft.Expression.Platform.Silverlight.SilverlightPlatformSpecificView.OnUnhandledException(Object sender, ViewUnhandledExceptionEventArgs args)
   at System.EventHandler`1.Invoke(Object sender, TEventArgs e)
   at Microsoft.Expression.Platform.Silverlight.Host.SilverlightImageHost.<>c__DisplayClass1.<Application_UnhandledException>b__0(Object o)
   at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)
The Extender Provider failed to return an Extender for this object.
   at MS.Internal.XcpImports.CheckHResult(UInt32 hr)
   at MS.Internal.XcpImports.Collection_InsertValue[T](PresentationFrameworkCollection`1 collection, UInt32 index, CValue value)
   at MS.Internal.XcpImports.Collection_InsertDependencyObject[T](PresentationFrameworkCollection`1 collection, UInt32 index, DependencyObject value)
   at System.Windows.PresentationFrameworkCollection`1.InsertDependencyObject(Int32 index, DependencyObject value)
   at System.Windows.Controls.UIElementCollection.InsertInternal(Int32 index, UIElement value)
   at Microsoft.Expression.Platform.Silverlight.Host.SilverlightImageHost.SceneWrapper.set_SceneRoot(FrameworkElement value)
   at Microsoft.Expression.Platform.Silverlight.Host.SilverlightImageHost.set_RootInstance(Object value)

I can work around it by just
  • not inheriting radwindow
  • creating a usercontrol and then
  • instantiating a radwindow
  • assigning the content of the radwindow to the usercontrol

But i prefer seeing the radwindow border in the desginer
is there anything obvious i am doing wrong


3 Answers, 1 is accepted

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Telerik team
answered on 09 Mar 2011, 01:13 PM
Hello David Ocasio,

I've tried to reproduce this issue but to no avail. I've attached my test projects, could you please download the attachment and examine it?

the Telerik team
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David Ocasio
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answered on 19 Mar 2011, 03:24 PM
sorry so late for a continuation of the thread


i think i have found the answer or at least a direction

with the release of 2011 q1 i felt the need to remove all othe older versions of radcontrols instead of just upgrading the projects
i also removed the extentions and deleted the roaming appdata telerik uses

it seems for now that this is working
i can now inhertit the radwindow and have it display in the designer properly

if this changes of course i will be back lol

thanks for your assitance
Telerik team
answered on 21 Mar 2011, 09:20 AM
Hello David Ocasio,

I'm glad you managed to fix the problem.

Please contact us again should you have any other issues.

the Telerik team
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David Ocasio
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Answers by
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David Ocasio
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