WPF Datagrid [System.Windows.Data Error: 4]

Question

I have a WPF application with a DataGrid as shown below:

Datagrid (simplified):

<DataGrid x:Name="CoreServiceLogDataGrid"
Grid.Row="0"
Height="auto"
ItemsSource="{Binding Source={StaticResource CoreServiceCollection}}"
AutoGenerateColumns="False"
CanUserReorderColumns="True"
CanUserSortColumns="True"
IsReadOnly="True">

    <DataGrid.Columns>
        <DataGridTextColumn x:Name="ID"
            Header="ID"
            Binding="{Binding ID}" />

        <DataGridTextColumn Binding="{Binding Timestamp}"
            Header="Timestamp" />

    </DataGrid.Columns>

</DataGrid>

when the Data is loaded; I get the following Error (numerous times):

System.Windows.Data Error: 4 : Cannot find source for binding with reference 'RelativeSource FindAncestor, AncestorType='System.Windows.Controls.DataGrid', AncestorLevel='1''. BindingExpression:Path=AreRowDetailsFrozen; DataItem=null; target element is 'DataGridDetailsPresenter' (Name=''); target property is 'SelectiveScrollingOrientation' (type 'SelectiveScrollingOrientation')
System.Windows.Data Error: 4 : Cannot find source for binding with reference 'RelativeSource FindAncestor, AncestorType='System.Windows.Controls.DataGrid', AncestorLevel='1''. BindingExpression:Path=HeadersVisibility; DataItem=null; target element is 'DataGridRowHeader' (Name=''); target property is 'Visibility' (type 'Visibility')

I have No Idea why this occurs and how to FIX this.

EDIT: (Info about CoreServiceLogViewCollection)

CoreServiceCollection is just a ListCollectionView.

  public static ListCollectionView CoreServiceLogViewCollection {
        get {
            if (_coreServiceCollection == null) {
                _coreServiceCollection =
                    new ListCollectionView(LogSession.CoreServiceLogCollection);
            }

            return _coreServiceCollection;
        }
    }

the parameter is just an ObservableCollection containing ID,Timestamp and other properties

EDIt2: The instantiation is done in App.xaml:

   <ResourceDictionary>
       <x:Static Member="vm2:CoreServiceLogView.CoreServiceLogViewCollection"
                          x:Key="CoreServiceCollection" />
   </ResourceDictionary>

EDIT 3 (The Style... )

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
                xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
                mc:Ignorable="d">


<!-- #columnHeaderDGStyle -->


<!-- Datagrid -->
<Style x:Key="Log4NetDataGridStyle"
       TargetType="DataGrid">

    <Setter Property="ColumnHeaderStyle"
            Value="{DynamicResource DatagridColumnHeaderCustomTemplateStyle}" />


    <Setter Property="RowStyle"
            Value="{DynamicResource Log4NetRowStyle}" />

    <Setter Property="RowDetailsTemplate"
            Value="{DynamicResource RowDetailsTemplate}" />

    <Setter Property="MaxHeight"
            Value="1600">
    </Setter>
    <Setter Property="MaxWidth"
            Value="2560">
    </Setter>


</Style>


<Style x:Key="DataCommuGridStyle"
       TargetType="DataGrid">

    <Setter Property="ColumnHeaderStyle"
            Value="{DynamicResource DatagridColumnHeaderCustomTemplateStyle}" />


    <Setter Property="RowStyle"
            Value="{DynamicResource CommuRowStyle}" />

    <Setter Property="RowDetailsTemplate"
            Value="{DynamicResource RowDetailsTemplate}" />

    <Setter Property="MaxHeight"
            Value="1600">
    </Setter>
    <Setter Property="MaxWidth"
            Value="2560">
    </Setter>


</Style>


<!-- ************************* Row Style ************************* -->
<Style x:Key="Log4NetRowStyle"
       TargetType="DataGridRow">

    <Setter Property="FontSize"
            Value="14" />

    <Setter Property="Background"
            Value="{Binding Path=LogColour.ColorName}" />

    <Setter Property="Height"
            Value="Auto">
    </Setter>

    <Style.Triggers>
        <DataTrigger></DataTrigger>
    </Style.Triggers>

</Style>

<Style x:Key="CommuRowStyle"
       TargetType="DataGridRow">

    <Setter Property="FontSize"
            Value="14" />

    <Setter Property="Background"
            Value="Azure" />

    <Setter Property="Height"
            Value="Auto">
    </Setter>

    <Style.Triggers>
        <DataTrigger></DataTrigger>
    </Style.Triggers>

</Style>


<DataTemplate x:Key="RowDetailsTemplate">
    <Border BorderThickness="0"
            Padding="5" >


        <Border.Background>
            <LinearGradientBrush StartPoint="0,0"
                                 EndPoint="0,1" Opacity="0.2">
                <GradientStop Color="White"
                              Offset="0" />
                <GradientStop Color="Black"
                              Offset="1" />
            </LinearGradientBrush>

        </Border.Background>


        <!-- alternative with Expancer -->
        <Expander IsExpanded="True"
                  HorizontalAlignment="Left"
                  BorderThickness="1,1,1,5"
                  MaxHeight="300"
                  MaxWidth="900">

            <Expander.Header>
                <DockPanel>
                    <TextBlock FontSize="12"
                               Text="LoggingMessage: "
                               VerticalAlignment="Center" />
                </DockPanel>
            </Expander.Header>

            <Expander.Content>
                <ScrollViewer VerticalScrollBarVisibility="Auto"
                              HorizontalScrollBarVisibility="Auto"
                              CanContentScroll="True"
                              Style="{StaticResource LeftScrollViewer}">
                    <StackPanel Orientation="Vertical">

                        <TextBox FontSize="16"
                                 BorderThickness="0"
                                 IsReadOnly="True"
                                 Background="Transparent"
                                 Foreground="Black"
                                 TextWrapping="Wrap"
                                 Text="{Binding LoggingMessage, Mode=OneWay}" />
                    </StackPanel>
                </ScrollViewer>
            </Expander.Content>
        </Expander>


    </Border>


</DataTemplate>


<Style x:Key="GroupHeaderStyle"
       TargetType="{x:Type GroupItem}">
    <Setter Property="Margin"
            Value="0,0,0,5" />
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type GroupItem}">
                <Expander IsExpanded="False"
                          Background="#FF112255"
                          BorderBrush="#FF002255"
                          Foreground="Black"
                          BorderThickness="1,1,1,5">
                    <Expander.Header>
                        <DockPanel>
                            <TextBlock FontWeight="Bold"
                                       Foreground="White"
                                       Text="{Binding Path=Name}"
                                       Margin="5,0,0,0"
                                       Width="100" />
                            <TextBlock FontWeight="Bold"
                                       Foreground="White"
                                       Text="{Binding Path=ItemCount}" />
                        </DockPanel>
                    </Expander.Header>

                    <Expander.Content>
                        <ItemsPresenter />
                    </Expander.Content>
                </Expander>


            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>


<!-- ******************** DataTemplate ******************** -->


</ResourceDictionary>

Answer 1

I wrote an answer a while back about how to read WPF binding errors. Basically, break down your error on the semi-colons and start reading it from the bottom up, and it should give you some idea where the binding error is:

• System.Windows.Data Error: 4 :
  • Cannot find source for binding with reference 'RelativeSource FindAncestor, AncestorType='System.Windows.Controls.DataGrid', AncestorLevel='1''. BindingExpression:Path=AreRowDetailsFrozen;
• DataItem=null;
• target element is 'DataGridDetailsPresenter' (Name='');
• target property is 'SelectiveScrollingOrientation' (type 'SelectiveScrollingOrientation')

and

• System.Windows.Data Error: 4 :
  • Cannot find source for binding with reference 'RelativeSource FindAncestor, AncestorType='System.Windows.Controls.DataGrid', AncestorLevel='1''. BindingExpression:Path=HeadersVisibility;
• DataItem=null;
• target element is 'DataGridRowHeader' (Name='');
• target property is 'Visibility' (type 'Visibility')

Reading from the bottom up, the first error is telling you

• the property containing the binding causing the error is SelectiveScrollingOrientation
• the UI object containing the problematic property is a DataGridDetailsPresenter, with no name specified
• the DataContext behind the UI object is null
• the binding is trying to find a RelativeSource of type DataGrid so it can bind to the AreRowDetailsFrozen property, and its failing to find that RelativeSource

So look through your code for something resembling this:

<DataGridDetailsPresenter SelectiveScrollingOrientation="{Binding 
    Path=AreRowDetailsFrozen, 
    RelativeSource={RelativeSource AncestorType={x:Type DataGrid}}" />

The second error is telling you

• the property containing the binding causing the error is Visibility
• the UI object containing the problematic property is a DataGridRowHeader, with no name specified
• the DataContext behind the UI object is null
• the binding is trying to find a RelativeSource of type DataGrid so it can bind to the HeadersVisibility property, and its failing to find that RelativeSource

So look through your code for something resembling this:

<DataGridRowHeader Visibility="{Binding 
    Path=HeadersVisibility, 
    RelativeSource={RelativeSource AncestorType={x:Type DataGrid}}" />

Based on the code you posted, the first may be in your LeftScrollViewer style somewhere, and the 2nd is probably in your DatagridColumnHeaderCustomTemplateStyle

If you have problems finding the error in your XAML, you can try running your application and inspecting it with a tool like Snoop that will let you look at the VisualTree of a WPF application while it's running, and you should be able to find the exact binding error there so you can trace it back to the source in your XAML