Add rows to a table dynamically in existing word document using OpenXml

Alright this should help you. I'm sure there are other ways of adding rows to an existing table, but this is the one I use.

I'm assuming in this example, that your table header is exatcly 1 row. And in this example I've put a bookmark called "table" inside my table in Word. It doesn't really matter where in the table, seeing as I'm digging out through Parent until I arrive at the table.

My original word document:

Code with comments explaining it:

//setup
using (var wordDoc = WordprocessingDocument.Open(@"C:\test\cb\exptable.docx", true))
{
    MainDocumentPart mainPart = wordDoc.MainDocumentPart;
    var document = mainPart.Document;
    var bookmarks = document.Body.Descendants<BookmarkStart>();

    //find bookmark
    var myBookmark = bookmarks.First(bms => bms.Name == "table");
    //dig through parent until we hit a table
    var digForTable = myBookmark.Parent;
    while(!(digForTable is Table))
    {
        digForTable = digForTable.Parent;
    }
    //get rows
    var rows = digForTable.Descendants<TableRow>().ToList();
    //remember you have a header, so keep row 1, clone row 2 (our template for dynamic entry)
    var myRow = (TableRow)rows.Last().Clone();
    //remove it after cloning.
    rows.Last().Remove();
    //do stuf with your row and insert it in the table
    for (int i = 0; i < 10; i++)
    {
        //clone our "reference row"
        var rowToInsert = (TableRow)myRow.Clone();
        //get list of cells
        var listOfCellsInRow = rowToInsert.Descendants<TableCell>().ToList();
        //just replace every bit of text in cells with row-number for this example
        foreach(TableCell cell in listOfCellsInRow)
        {
            cell.Descendants<Text>().FirstOrDefault().Text = i.ToString();
        }
        //add new row to table, after last row in table
        digForTable.Descendants<TableRow>().Last().InsertAfterSelf(rowToInsert);
    }
}

Document after running code:

That should do the trick.