[Solved] Problems with setting DataGridTemplateColumn's CellContentTemplate dynamically

[Yuri]

Hello.

I have a RadDataGrid with a single DataGridTemplateColumn.
I am trying to dynamically generate the DataTemplate for the column's cells and assign it to the CellContentTemplate in runtime.
DataTemplate is created by assembling its textual representation using a StringBuilder, and then calling 
                 dataTemplate = (DataTemplate)XamlReader.Load(stringBuilder.ToString());

The problem is that when the template contains anything beyond some rudimentary elements, I get a XAML exception.

I tried to implement this DataTemplate assignment in 2 different ways:
1. When the page is loaded, generate the DataTemplate and just assign (dataGrid.Columns[0] as DataGridTemplateColumn).CellContentTemplate = dataTemplate.
2. Implement a DataTemplateSelector whose SelectTemplateCore method returns the dynamically resolved DataTemplate.
The both approaches result in the same exception.

The following DataTemplate definition works:
                StringBuilder stringBuilder = new StringBuilder();
                stringBuilder.Append("<DataTemplate xmlns=\"http://schemas.microsoft.com/winfx/2006/xaml/presentation\">");
                stringBuilder.Append("<Grid>");
                stringBuilder.Append("<Grid Margin=\"30,12,10,12\">");
                stringBuilder.Append("<StackPanel Orientation=\"Horizontal\">");
                stringBuilder.Append("</StackPanel>");
                stringBuilder.Append("</Grid>");
                stringBuilder.Append("</Grid>");
                stringBuilder.Append("</DataTemplate>");

The following, though, results in an exception:
                StringBuilder stringBuilder = new StringBuilder();
                stringBuilder.Append("<DataTemplate xmlns=\"http://schemas.microsoft.com/winfx/2006/xaml/presentation\">");
                stringBuilder.Append("<Grid>");
                stringBuilder.Append("<Grid Margin=\"30,12,10,12\">");
                stringBuilder.Append("<StackPanel Visibility=\"{Binding Converter={StaticResource EmptyPatientListToVisibilityConverter}, ConverterParameter=True}\">");
                stringBuilder.Append("</StackPanel>");
                stringBuilder.Append("</Grid>");
                stringBuilder.Append("</Grid>");
                stringBuilder.Append("</DataTemplate>");

The converter is declared in the XAML file of the same code-behind:
         <converters:EmptyPatientListToVisibilityConverter x:Key="EmptyPatientListToVisibilityConverter"/>

The exception is:
"The text associated with this error code could not be found.\r\n\r\nElement is already the child of another element. [Line: 1 Position: 126]"
with the stack trace:
   at Windows.UI.Xaml.DataTemplate.LoadContent()
   at Telerik.UI.Xaml.Controls.Grid.DataGridTemplateColumn.CreateContainer(Object rowItem)
   at Telerik.UI.Xaml.Controls.Grid.View.XamlContentLayer.GenerateCellContainer(Object rowItem, DataGridColumn definition)
   at Telerik.UI.Xaml.Controls.Grid.XamlGridCellGenerator.Telerik.UI.Xaml.Controls.Grid.IUIContainerGenerator<Telerik.UI.Xaml.Controls.Grid.GridCellModel,Telerik.UI.Xaml.Controls.Grid.CellGenerationContext>.GenerateContainerForItem(CellGenerationContext info, Object containerType)
   at Telerik.UI.Xaml.Controls.Grid.CellModelGenerator.GenerateContainerForItem(CellGenerationContext context, Object containerType)
   at Telerik.UI.Xaml.Controls.Grid.ItemModelGenerator`2.GenerateContainer(K context)
   at Telerik.UI.Xaml.Controls.Grid.CellsController`1.GetCellDecorator(IItemInfoNode parentRow, ItemInfo columnItemInfo, Int32 rowLine, Int32 columnLine)
   at Telerik.UI.Xaml.Controls.Grid.CellsController`1.GenerateCellsForRow(IItemInfoNode rowDecorator, Int32 rowSlot)
   at Telerik.UI.Xaml.Controls.Grid.Model.GridModel.GenerateCellsForReadOnlyRow(Int32 rowSlot, Double largestRowElementWidth, IItemInfoNode rowDecorator)
   at Telerik.UI.Xaml.Controls.Grid.Model.GridModel.Telerik.UI.Xaml.Controls.Grid.ITable.GenerateCellsForRow(Int32 rowSlot, Double largestRowElementHeight, IItemInfoNode rowDecorator)
   at Telerik.UI.Xaml.Controls.Grid.NodePool`2.GenerateCellsForLine(Int32 slot, Double largestLength, T lastElement)
   at Telerik.UI.Xaml.Controls.Grid.NodePool`2.GenerateContainer(IList`1 itemInfos)
   at Telerik.UI.Xaml.Controls.Grid.NodePool`2.MeasureForward(MeasureContext& context)
   at Telerik.UI.Xaml.Controls.Grid.NodePool`2.MeasureVertically(RadSize availableSize, Double offset)
   at Telerik.UI.Xaml.Controls.Grid.NodePool`2.OnMeasure(RadSize availableSize, Double offset)
   at Telerik.UI.Xaml.Controls.Grid.Model.GridModel.MeasureCells(RadSize newAvailableSize)
   at Telerik.UI.Xaml.Controls.Grid.RadDataGrid.OnCellsPanelMeasure(RadSize newAvailableSize)
   at Telerik.UI.Xaml.Controls.Grid.Primitives.DataGridCellsPanel.MeasureOverride(Size availableSize)
   at Windows.UI.Xaml.UIElement.Measure(Size availableSize)
   at Telerik.UI.Xaml.Controls.Grid.Primitives.DataGridRootPanel.MeasureOverride(Size availableSize)
   at Windows.UI.Xaml.FrameworkElement.MeasureOverride(Size availableSize)
   at Telerik.UI.Xaml.Controls.RadControl.MeasureOverride(Size availableSize)


Please advise.

[Yuri]

Hmmmm...
Turns out that moving the converter declaration from the page's XAML file to StandardStyles.xaml solves the issue.
Not very intuitive, and goes against the encapsulation idea...