How can I add tables to a WPF RichTextBox programmatically?

I'm trying to make a RichTextBox that has some common word processing features, namely tables. It doesn't seem like there is direct support for it, but documentation seems to point to the idea that whatever you can do with FlowDocuments you can do with RichTextBoxes.

Ideally, the user will press a button on a toolbar above the text box, and a table will be created at the caret position in the rich text box.

Here's what I have in the xaml related to the text box and toolbar button so far:

            <DockPanel>
                <ToolBar Height="30" DockPanel.Dock="Top">
                    <Button Style="{StaticResource formatImageStyle}" Click="InsertTable" ToolTip="Insert Table">
                        <Image Source="/resources/images/table.png"></Image>
                    </Button>
                </ToolBar>
                <RichTextBox x:Name="rtb" SpellCheck.IsEnabled="True" AcceptsTab="True" Margin="10,5,10,0" FontSize="16" MinHeight="350" MaxHeight="350" VerticalScrollBarVisibility="Auto"></RichTextBox>
            </DockPanel>

Lastly, here's what I have in the xaml.cs so far. I haven't messed with the caret position yet because I just wanted to try to get a table in the box first.

        private void InsertTable(object sender, RoutedEventArgs e)
        {
            rtb.BeginChange();
            var table = new Table();

            table.Columns.Add(new TableColumn());
            table.Columns.Add(new TableColumn());
            table.Columns.Add(new TableColumn());

            table.RowGroups.Add(new TableRowGroup());
            table.RowGroups[0].Rows.Add(new TableRow());
            table.RowGroups[0].Rows.Add(new TableRow());
            table.RowGroups[0].Rows.Add(new TableRow());

            rtb.Document.Blocks.Add(table);
            rtb.EndChange();
        }

Thanks!

I followed documentation to create a table, and then added it to the RichTextBox by typing:
richTextBoxName.Document.Blocks.Add(tableName);

Expecting to see the table get added. Instead, nothing happened. I confirmed the code was being executed.

I also checked to see if I was setting up the code correctly to add things progammatically, and this code snippet I tried worked:

            rtb.BeginChange();

            TextPointer tp2 = rtb.CaretPosition.GetPositionAtOffset(0, LogicalDirection.Forward);
            rtb.CaretPosition.InsertTextInRun("test");
            rtb.CaretPosition = tp2;
            rtb.EndChange();
            Keyboard.Focus(rtb);

I tried adding BeginChange() and EndChange() to the xaml.cs snippet above, but that didn't work either.

You didn't add cells to the rows, try this:

private void InsertTable(object sender, RoutedEventArgs e)
        {
            rtb.BeginChange();
            var table = new Table();
            var gridLenghtConvertor = new GridLengthConverter();
            table.Columns.Add(new TableColumn() );
            table.Columns.Add(new TableColumn() );
            table.Columns.Add(new TableColumn() );

            table.RowGroups.Add(new TableRowGroup());
            for (int i = 0; i < 3; i++)
            {
                table.RowGroups[0].Rows.Add(new TableRow());
                table.RowGroups[0].Rows[i].Cells.Add(new TableCell());
                table.RowGroups[0].Rows[i].Cells.Add(new TableCell());
                table.RowGroups[0].Rows[i].Cells.Add(new TableCell());
            }
            rtb.Document.Blocks.Add(table);
            rtb.EndChange();
        }

This will add an empty table but you can see it if you select the text or press CTRL+A. You can add text to a cell like this

private void InsertTable(object sender, RoutedEventArgs e)
        {
            rtb.BeginChange();
            var table = new Table();
            var gridLenghtConvertor = new GridLengthConverter();
            table.Columns.Add(new TableColumn() );
            table.Columns.Add(new TableColumn() );
            table.Columns.Add(new TableColumn() );

            table.RowGroups.Add(new TableRowGroup());
            for (int i = 0; i < 3; i++)
            {
                table.RowGroups[0].Rows.Add(new TableRow());
                table.RowGroups[0].Rows[i].Cells.Add(new TableCell(new Paragraph(new Run("Row" + (i + 1).ToString() + " Column1"))));
                table.RowGroups[0].Rows[i].Cells.Add(new TableCell(new Paragraph(new Run("Row" + (i + 1).ToString() + " Column2"))));
                table.RowGroups[0].Rows[i].Cells.Add(new TableCell(new Paragraph(new Run("Row" + (i + 1).ToString() + " Column3"))));
            }
            rtb.Document.Blocks.Add(table);
            rtb.EndChange();
        }