Prefix 'xcdg' does not map to a namespace

Question

I recently started playing with DataGridControl from Extended WPF Toolkit

<Grid x:Name="LayoutRoot" DataContext="{Binding Source={StaticResource SampleDataSource}}">
    <xcdg:DataGridControl ItemsSource="{Binding Orders}" SelectionMode="Single" >
        <xcdg:DataGridControl.View>
            <xcdg:TableflowView FixedColumnCount="1" UseDefaultHeadersFooters="True" ShowRowSelectorPane="False" VerticalGridLineBrush="Green" VerticalGridLineThickness="2" HorizontalGridLineBrush="Purple" HorizontalGridLineThickness="2">
                <xcdg:TableflowView.Theme>
                    <xcdg:ZuneNormalColorTheme/>
                </xcdg:TableflowView.Theme>
            </xcdg:TableflowView>
        </xcdg:DataGridControl.View>
        <xcdg:DataGridControl.Columns>
            <xcdg:Column FieldName="OrderID" IsMainColumn="True"/>
            <xcdg:Column FieldName="ExternalID" />
            <xcdg:Column FieldName="CustomerName" />
            <xcdg:Column FieldName="Date" />
            <xcdg:Column FieldName="Address" />
            <xcdg:Column FieldName="Items" Width="*" />
        </xcdg:DataGridControl.Columns>
    </xcdg:DataGridControl>
</Grid>

It's ok and everything works. Then I added style.

<Style TargetType="{x:Type xcdg:DataGridControl}">
    <Setter Property="Background" Value="MediumOrchid"/>
</Style>

Style is applied and everything works again. So what I did next was creating CotrolTemplate using Expression Blend and added that template to my Style.

<Style TargetType="{x:Type xcdg:DataGridControl}">
  <Setter Property="Background"
          Value="MediumOrchid" />
  <Setter Property="Template">
    <Setter.Value>
      <ControlTemplate TargetType="{x:Type xcdg:DataGridControl}">
        <Grid>
          <Border BorderBrush="{TemplateBinding BorderBrush}"
                  BorderThickness="{TemplateBinding BorderThickness}"
                  Background="{TemplateBinding Background}">
            <AdornerDecorator x:Name="PART_DragDropAdornerDecorator">
              <xcdg:TableViewScrollViewer x:Name="PART_ScrollViewer"
                                          Padding="{TemplateBinding Padding}"
                                          RowSelectorPaneWidth="{Binding (xcdg:DataGridControl.DataGridContext).RowSelectorPaneWidth, RelativeSource={RelativeSource Self}}"
                                          ShowRowSelectorPane="{Binding (xcdg:DataGridControl.DataGridContext).ShowRowSelectorPane, RelativeSource={RelativeSource Self}}">
                <xcdg:TableflowViewItemsHost />
              </xcdg:TableViewScrollViewer>
            </AdornerDecorator>
          </Border>
          <Grid x:Name="connectionStateGrid"
                HorizontalAlignment="Right"
                Height="30"
                Margin="0,0,25,25"
                VerticalAlignment="Bottom"
                Width="30">
            <ContentPresenter x:Name="connectionStateLoadingContentPresenter"
                              ContentTemplate="{Binding (xcdg:DataGridControl.DataGridContext).ConnectionStateLoadingGlyph, RelativeSource={RelativeSource Self}}"
                              Content="{TemplateBinding ConnectionState}"
                              Visibility="Collapsed" />
            <ContentPresenter x:Name="connectionStateCommittingContentPresenter"
                              ContentTemplate="{Binding (xcdg:DataGridControl.DataGridContext).ConnectionStateCommittingGlyph, RelativeSource={RelativeSource Self}}"
                              Content="{TemplateBinding ConnectionState}"
                              Visibility="Collapsed" />
            <ContentPresenter x:Name="connectionStateErrorContentPresenter"
                              ContentTemplate="{Binding (xcdg:DataGridControl.DataGridContext).ConnectionStateErrorGlyph, RelativeSource={RelativeSource Self}}"
                              Content="{TemplateBinding ConnectionState}"
                              Visibility="Collapsed" />
          </Grid>
        </Grid>
        <ControlTemplate.Triggers>
          <DataTrigger Binding="{Binding (xcdg:DataGridControl.DataGridContext).IsConnectionStateGlyphEnabled, RelativeSource={RelativeSource Self}}"
                       Value="False">
            <Setter Property="Visibility"
                    TargetName="connectionStateGrid"
                    Value="Collapsed" />
          </DataTrigger>
          <DataTrigger Binding="{Binding (xcdg:DataGridControl.DataGridContext).DataGridControl.ConnectionState, RelativeSource={RelativeSource Self}}"
                       Value="Loading">
            <Setter Property="Visibility"
                    TargetName="connectionStateLoadingContentPresenter"
                    Value="Visible" />
            <Setter Property="Visibility"
                    TargetName="connectionStateErrorContentPresenter"
                    Value="Collapsed" />
            <Setter Property="Visibility"
                    TargetName="connectionStateCommittingContentPresenter"
                    Value="Collapsed" />
          </DataTrigger>
          <DataTrigger Binding="{Binding (xcdg:DataGridControl.DataGridContext).DataGridControl.ConnectionState, RelativeSource={RelativeSource Self}}"
                       Value="Committing">
            <Setter Property="Visibility"
                    TargetName="connectionStateLoadingContentPresenter"
                    Value="Collapsed" />
            <Setter Property="Visibility"
                    TargetName="connectionStateErrorContentPresenter"
                    Value="Collapsed" />
            <Setter Property="Visibility"
                    TargetName="connectionStateCommittingContentPresenter"
                    Value="Visible" />
          </DataTrigger>
          <DataTrigger Binding="{Binding (xcdg:DataGridControl.DataGridContext).DataGridControl.ConnectionState, RelativeSource={RelativeSource Self}}"
                       Value="Error">
            <Setter Property="Visibility"
                    TargetName="connectionStateLoadingContentPresenter"
                    Value="Collapsed" />
            <Setter Property="Visibility"
                    TargetName="connectionStateErrorContentPresenter"
                    Value="Visible" />
            <Setter Property="Visibility"
                    TargetName="connectionStateCommittingContentPresenter"
                    Value="Collapsed" />
          </DataTrigger>
        </ControlTemplate.Triggers>
      </ControlTemplate>
    </Setter.Value>
  </Setter>
</Style>

But now whole ControlTemplate is underlined and it says

Prefix 'xcdg' does not map to a namespace.

there is

xmlns:xcdg="http://schemas.xceed.com/wpf/xaml/datagrid"

both in my resource dictionary and window. Also xaml designer throws exception in 'MainWindow.xaml' where 'DataGridControl' is placed. It's

ArgumentException: '{DependencyProperty.UnsetValue}' is not a valid value for the 'System.Windows.Controls.Control.Template' property on a Setter.

At runtime it works fine. All happened after I added ControlTemplate to Style of DataGridControl. Any explanation why is this happening or how to avoid this will be highly appreciated.

Answer 1

Seems like this issue still exists in VS2017. the exception is raised when using binding to dependency properties with namespace.

the solution I found is to explicitly add Path= to the binding.

Original code:

<DataTrigger Binding="{Binding (xcdg:DataGridControl.DataGridContext).IsConnectionStateGlyphEnabled, RelativeSource={RelativeSource Self}}" Value="False">

Modified code:

<DataTrigger Binding="{Binding Path=(xcdg:DataGridControl.DataGridContext).IsConnectionStateGlyphEnabled, RelativeSource={RelativeSource Self}}" Value="False">

I've found the solution in Heinrich Ulbricht Blog