DataGrid within ListBox ItemTemplate not inheriting bindings?

Question

I've got some nested controls that don't seem to be inheriting bindings correctly... or it could be something else entirely. I'm a bit new to WPF.

I've got an ObservableCollection of objects bound to the ListBox and at the top level this appears to be working since a row is added for each item in the collection as expected. The problem is that I need to place a DataGrid within the ListBox's ItemTemplate and...

All I get are the headers, which I specified manually. No data from the bound objects.

I've probably just done something dumb. Here's the code, slightly simplified:

XAML:

<ListBox x:Name="ReportListBox" Margin="10,10,10,10" Grid.Row="1" ItemsSource="{Binding Path=SummaryTotals, Mode=OneWay}">
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <DataGrid>
                        <DataGrid.Columns>
                            <DataGridTextColumn Binding="{Binding Date, StringFormat=\{0:MM/dd/yyyy\}}" Header="Date"/>
                            <DataGridTextColumn Binding="{Binding GrossRevenue}" Header="Gross Revenue" />
                            <DataGridTextColumn Binding="{Binding OurRevenue}" Header="Our Revenue" />
                            <DataGridTextColumn Binding="{Binding Cost}" Header="Cost" />
                            <DataGridTextColumn Binding="{Binding Profit}" Header="Profit" />
                            <DataGridTextColumn Binding="{Binding Roi}" Header="ROI" />
                            <DataGridTextColumn Binding="{Binding Rpc}" Header="RPC" />
                            <DataGridTextColumn Binding="{Binding Clicks}" Header="Clicks" />
                            <DataGridTextColumn Binding="{Binding Conversions}" Header="Conversions" />
                            <DataGridTextColumn Binding="{Binding ConversionRate}" Header="Conversion Rate" />
                        </DataGrid.Columns>
                    </DataGrid>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>

C#:

public class SummaryTotalRecord
        {
            public DateTime Date { get; set; }
            public decimal Cost { get { return Google.Cost + Ypa.PureLocal.Cost + Ypa.BuyerPricer.Cost; } }
            public decimal GrossRevenue { get { return Google.GrossRevenue + Ypa.PureLocal.GrossRevenue + Ypa.BuyerPricer.GrossRevenue; } }
            public decimal OurRevenue { get { return Google.OurRevenue + Ypa.PureLocal.OurRevenue + Ypa.BuyerPricer.OurRevenue; } }
            public decimal Roi { get { return (Google.Roi + Ypa.PureLocal.Roi + Ypa.BuyerPricer.Roi)/3; } }
            public decimal ConversionRate { get { return (Google.ConversionRate + Ypa.PureLocal.ConversionRate + Ypa.BuyerPricer.ConversionRate)/3; } }
            public decimal Profit { get { return Google.Profit + Ypa.PureLocal.Profit + Ypa.BuyerPricer.Profit; } }
            public decimal Rpc { get { return (Google.Rpc + Ypa.PureLocal.Rpc + Ypa.BuyerPricer.Rpc)/3; } }
            public long Clicks { get { return Google.Clicks + Ypa.PureLocal.Clicks + Ypa.BuyerPricer.Clicks; } }
            public long Conversions { get { return Google.Conversions + Ypa.PureLocal.Conversions + Ypa.BuyerPricer.Conversions; } }
            // ... plus a bunch of other properties I haven't touched yet
        }

public ObservableCollection<SummaryTotalRecord> SummaryTotals = new ObservableCollection<SummaryTotalRecord>();

I found others with similar problems and the accepted fix seems to be something like

RelativeSource={RelativeSource Mode=FindAncestor,AncestorType={x:Type ListBox}}

But neither that, nor x:Type ListItem seems to produce any difference in results.

Update: Trying a new method with similar results. I've changed my class to return a DataTable called TableData and modified the XAML like so:

<Expander IsExpanded="True" Header="{Binding Date, StringFormat=\{0:MM/dd/yyyy\}}">
                        <DataGrid DataContext="{Binding Path=TableData}" AutoGenerateColumns="True" />
                    </Expander>

Similar results:

The Expander has access to the Date property, but the DataGrid it contains doesn't have access to TableData ?

Answer 1

I ended up adding a new property to the bound object:

public DataTable TableData { get { var table = new DataTable();

                table.Columns.Add("Date", typeof (string));
                table.Columns.Add("Gross Revenue", typeof(string));
                table.Columns.Add("Our Revenue", typeof(string));
                table.Columns.Add("Cost", typeof(string));
                table.Columns.Add("Profit", typeof(string));
                table.Columns.Add("ROI", typeof(string));
                table.Columns.Add("RPC", typeof(string));
                table.Columns.Add("Clicks", typeof(long));
                table.Columns.Add("Conversions", typeof(long));
                table.Columns.Add("Conversion Rate", typeof(string));

                table.Rows.Add(
                    Date.ToString("MM/dd/yyyy"),
                    GrossRevenue.ToString("C"),
                    OurRevenue.ToString("C"),
                    Cost.ToString("C"),
                    Profit.ToString("C"),
                    Roi.ToString("P"),
                    Rpc.ToString("P"),
                    Clicks,
                    Conversions,
                    ConversionRate.ToString("P")
                );

                return table;
            }
        }

At which point the following XAML worked:

<DataGrid ItemsSource="{Binding Path=TableData}" AutoGenerateColumns="True" 
CanUserAddRows="False" />

I still have no idea why the original code failed and this code works.

Answer 2

It makes perfect sense why the Grid was empty; it wasn't bound to any collection. If the source isn't specified, then there is none, and the grid will be empty. This isn't something that can be inferenced by the binding engine.