We're generating a busy and complicated map with a lot of custom controls within an InformationLayer. Eventually after interacting with the custom controls (within the Information Layer) we're getting a NullReferenceException within -

Telerik.Windows.Controls.Map.MapCanvas.MeasureOverride(Size availableSize)

The full stack trace is:

System.NullReferenceException
  HResult=0x80004003
  Message=Object reference not set to an instance of an object.
  Source=Telerik.Windows.Controls.DataVisualization
  StackTrace:
   at Telerik.Windows.Controls.Map.MapCanvas.MeasureOverride(Size availableSize)
   at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
   at System.Windows.UIElement.Measure(Size availableSize)
   at System.Windows.ContextLayoutManager.UpdateLayout()
   at System.Windows.ContextLayoutManager.UpdateLayoutCallback(Object arg)
   at System.Windows.Media.MediaContext.InvokeOnRenderCallback.DoWork()
   at System.Windows.Media.MediaContext.FireInvokeOnRenderCallbacks()
   at System.Windows.Media.MediaContext.RenderMessageHandlerCore(Object resizedCompositionTarget)
   at System.Windows.Media.MediaContext.RenderMessageHandler(Object resizedCompositionTarget)
   at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)
   at System.Windows.Threading.DispatcherOperation.InvokeImpl()
   at System.Windows.Threading.DispatcherOperation.InvokeInSecurityContext(Object state)
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at MS.Internal.CulturePreservingExecutionContext.Run(CulturePreservingExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Windows.Threading.DispatcherOperation.Invoke()
   at System.Windows.Threading.Dispatcher.ProcessQueue()
   at System.Windows.Threading.Dispatcher.WndProcHook(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
   at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)
   at System.Windows.Threading.Dispatcher.LegacyInvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)
   at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
   at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
   at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr dwComponentID, Int32 reason, Int32 pvLoopData)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
   at System.Windows.Forms.Application.Run(Form mainForm)

It's hard to reproduce, or reproduce in a repeatitive fashion, but is there anyway we can either use a different pattern/place to have the controls or catch this exception? 

Due to the RtfFormatProvider not respecting the existence or lack of a newline Inline at the end of the last Paragraph of the RadDocument, copying sth that does not end with a newline adds an extra final newline marker ("\par") at the end of the copied RTF.

While RadRichTextBox handles this gracefully when pasting (by ignoring the extra "\par"), other applications, e.g. Wordpad, include that newline with the pasted contents.

For example, copying a single letter "L" from the middle of a sentence in a RadRichTextBox and pasting it in Wordpad, one will get "L" followed by an extra Paragraph.

Short of creating another RTF provider and filtering out that last "\par", can you suggest another way to avoid adding extra newlines when exporting non-closed paragraphs to RTF? I may have missed something, but there is no option to control that in the RtfFormatProvider code.

Thanks in advance!

I don't know how to wrap columns header using just a style. I cannot use code behind because we don't have code behind. We use MVVM and CaliburnMicro so we don't have code behind the view. So I was trying to apply style to the grid and wrap all the headers every time I add grid to the form but I cannot accomplish this task. I don't want to do wrap to every column every time I add the grid. So my Idea was but it doesn't work. Please advice.

<Style TargetType="telerik:GridViewDataColumn" >
        <Setter Property="Header">
            <Setter.Value>
                <DataTemplate>
                    <TextBlock TextWrapping="Wrap" Text="{Binding}"></TextBlock>
                </DataTemplate>
            </Setter.Value>
      </Setter>
 </Style>

 Thank you,

Grazyna

Is it possible to have both virtualization and smooth scrolling in TreeView. Application freezes when Treeview contains more items(nearly 500) and virtualized when scrolling. TreeView item template has more controls. If we disable virtualization, Loading Treeview takes more time (in minutes) and sometimes application crashes.

Need solution to have both virtualization(for fast initial loading) and smooth scrolling.

I have a popup shown below which has a ContentControl using a Template. In the ContentControl I want to concatenate two strings in the xaml.  I am using similar popups in different screens where only the Content varies with control name of the screen.I want to split this content into two static resources(static resource1=Plate Name , static resource2=can't contain special characters ) and want to use it in xaml as concatenated.

Is there any way to achieve this ? Any small help would be appreciated!

                        <Popup Name="PlateNameInvalidPopup" VerticalOffset="4">
                            <ContentControl Template="{StaticResource InvalidCharPopupTemplate}" 
                                Content="Plate Name can't contain special characters">
                            </ContentControl>
                        </Popup>

Is there any way to have the dropdown close itself after someone has selected an item in the gridview?  Effectively, I'd like a property called something like AllowMultiSelect, which I would set to false, and then the dropdown closes after the first item is selected.  Or maybe, if SelectionMode is set to Single, shouldn't the dropdown box close on its own after a selection is made?

Closing it manually during SelectionChanged works except in one case: where someone starts typing into the search box and then uses the mouse to select an item.  The incomplete search text doesn't get cleared out of the textbox - as if calling CloseDropDown() prevents cleanup from happening.

In any case, being able to make the multi column combobox behave like a single-select control would be great.  Any suggestions?  Thanks in advance.

[using the Q3 2018 release]

Hello,

If I write the following XAML code in a wizard page:

<Label Target="{Binding ElementName=txt_Code}"
            Text="Code:" />

<TextBox Name="txt_Code" />

The binding is not made between the Label and the TextBox and VS shows the following error:

Cannot find source for binding with reference 'ElementName=txt_Code'. BindingExpression:(no path); DataItem=null; target element is 'Label' (Name=''); target property is 'Target' (type 'UIElement').

PS: Sorry for the formatting, but the formatting options are not working on this page...

How can I add add a georeferenced bitmap image to a map?  This is a bitmap with known position (latitude and longitude of top left corner) and fixed pixel size (in degrees latitude and longitude).  The following code will place an image on the map (with the top left corner in the right spot):

<telerik:RadMap x:Name="radMap" ZoomLevel="14" Center="35.561852, -83.732723">
    <telerik:RadMap.Provider>
        <telerik:OpenStreetMapProvider StandardModeUserAgent=""/>
    </telerik:RadMap.Provider>
    <telerik:InformationLayer>
        <Image Source="/Images/sample.png" telerik:MapLayer.Location="35.561852, -83.732723">
            <telerik:MapLayer.HotSpot>
                <telerik:HotSpot X="0.0" Y="0.0" XUnits="Fraction" YUnits="Fraction" />
            </telerik:MapLayer.HotSpot>
        </Image>
    </telerik:InformationLayer>
</telerik:RadMap>

However, this obviously does not scale the image according to the pixel size in degrees.

Dear Developers,

Thank you very much for this library.

Although, could anyone tell if it is possible to preserve row details when exporting and having a button to toggle their visibility like it looks inside RadGridView?

Preview: https://i.imgur.com/xjXpTgL.png

For example, there is an option to add details using HTML exporting and appending to string like here https://docs.telerik.com/devtools/silverlight/controls/radgridview/events/export-events#exporting is shown, but this will make these details visible by default.

Is it possible to hide them by default and have something like a checkbox or button to show/hide these details in exported for each row?

Best regards