DataGrid RowHeader以编程方式设置 - 文本为空但设置了内容

Question

我正在以编程方式创建一个DataGrid，它工作正常，但RowHeaders没有正确显示。文本显然是因为工具提示显示正确的内容，但它在标题中显示为空白。显然我不能发布一个屏幕截图 - 它显示一个10行左右的网格，标题是150宽，但没有任何内容，然后是几列数据。

以下是创建DataGrid的代码：

            seisTraceHeaderGrid = new DataGrid
        {
            AutoGenerateColumns = false,
            HorizontalAlignment = HorizontalAlignment.Stretch,
            VerticalAlignment = VerticalAlignment.Stretch,
            HorizontalScrollBarVisibility = ScrollBarVisibility.Visible,
            VerticalScrollBarVisibility = ScrollBarVisibility.Visible,
            HorizontalContentAlignment = HorizontalAlignment.Stretch,
            HeadersVisibility = DataGridHeadersVisibility.All,
            IsReadOnly = true,
            CanUserAddRows = false,
            CanUserDeleteRows = false,
            CanUserReorderColumns = false,
            CanUserResizeColumns = true,
            CanUserResizeRows = true,
            CanUserSortColumns = false,
            SelectionMode = DataGridSelectionMode.Single,
            SelectionUnit = DataGridSelectionUnit.Cell,
            RowHeight = 25,
            ColumnWidth = 75,
        };

        seisTraceHeaderGrid.AlternatingRowBackground = (Brush)Resources["AlternateRowBackgroundBrush"];
        seisTraceHeaderGrid.ColumnHeaderStyle = (Style)Resources["ColumnHeaderStyle"];
        seisTraceHeaderGrid.LoadingRow += dg_LoadingRow;

        // set up the row headers
        DataTemplate rowHeaderTemplate = new DataTemplate();
        rowHeaderTemplate.DataType = typeof(RowHeaderNode);
        FrameworkElementFactory textHolder = new FrameworkElementFactory(typeof(Label));
        textHolder.SetBinding(ContentProperty, 
            new Binding("RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type DataGridRow}}, Path=Header"));
        rowHeaderTemplate.VisualTree = textHolder;
        seisTraceHeaderGrid.RowHeaderTemplate = rowHeaderTemplate;

        // add a column for each trace
        for (int traceId = 0; traceId < ViewModel.Nodes[0].Count; traceId++) {
            seisTraceHeaderGrid.Columns.Add(
                new DataGridTextColumn
                    {
                        Header = string.Format(" {0}", traceId + 1),
                        Binding = new Binding(string.Format("[{0}]", traceId))
                    }
                );
        }
        // add some dummy columns to make it prettier
        for (int traceId = ViewModel.Nodes[0].Count; traceId < 5; traceId++) {

            seisTraceHeaderGrid.Columns.Add(
                new DataGridTextColumn
                    {
                        Header = string.Format(" {0}", ""),
                        Binding = new Binding(string.Format("[{0}]", ""))
                    }
                );
        }

        seisTraceHeaderGrid.RowHeaderWidth = 150;
        seisTraceHeaderGrid.ItemsSource = ViewModel.Nodes;

        baseGrid.Children.Add(seisTraceHeaderGrid);

将文本放入RowHeader标签的方法：

    private void dg_LoadingRow(object sender, DataGridRowEventArgs e)
    {
        e.Row.Header = string.Format("[{0:000}]", ViewModel.RowHeaders[e.Row.GetIndex()].Offset) + " : " + ViewModel.RowHeaders[e.Row.GetIndex()].Name;
    }

我不在做什么？ TIA！

Janene