ASP.NET Dynamically creating HTMLTableColumns (headers)

try this:

HtmlTable table1 = new HtmlTable();

        // Set the table's formatting-related properties.
        table1.Border = 1;
        table1.CellPadding = 3;
        table1.CellSpacing = 3;
        table1.BorderColor = "red";

        // Start adding content to the table.
        HtmlTableRow row;
        HtmlTableCell cell;
        for (int i=1; i<=5; i++)
        {
                // Create a new row and set its background color.
                row = new HtmlTableRow();
                row.BgColor = (i%2==0 ? "lightyellow" : "lightcyan");
                for (int j=1; j<=4; j++)
                {
                        // Create a cell and set its text.
                        cell = new HtmlTableCell();
                        cell.InnerHtml = "Row: " + i.ToString()+ "<br />Cell: " + j.ToString();
                        // Add the cell to the current row.
                        row.Cells.Add(cell);
                }

                // Add the row to the table.
                table1.Rows.Add(row);
        }

        // Add the table to the page.
        this.Controls.Add(table1);

Yes in that name space you will want to look at:

HtmlTable
HtmlTableRow
HtmlTableCell

Use is like so:

        HtmlTable htmlTable = new HtmlTable();    //creating table object     
        HtmlTableRow htmlRow = new HtmlTableRow();   //creating row object
            HtmlTableCell htmlTableCell = new HtmlTableCell();   //create cell
            htmlTableCell.InnerHtml = "<b>Test Text Bolded</b>";//setting cell content
            HtmlTableCell textTableCell = new HtmlTableCell();  //create cell
            textTableCell.InnerText = "Test plain text";  //setting cell content

        htmlRow.Cells.Add(htmlTableCell);   //add cell to row
        htmlRow.Cells.Add(textTableCell);   //add cell to row
        htmlTable.Rows.Add(htmlRow);   // add row to table

HtmlTableCell = new HtmlTableCell("th");