How To Format Table In The Body Of Mail

Question

I am using C# for my problem.
I have an Excel file which has many worksheets. From "Fisrt Sheet", I am looking for a character "x" which will be present in some cells of a specific column (occurence of "x" will be in one specific column only, in different cells of that column). I am looking for "x" and extracting the corresponding row's details in a generic list (with naming the headers of extracted field). Now, I have to send this generic list in "tabular format" in body of the mail via Outlook.
I am getting the output but not in proper format. My code is extracting the information but I can't see any table borders and also the table headers are missing under which the extracted data should be filled.
Table header information should be like this:
Column 1 - MemoName
Column 1 - Type
Column 1 - Ext
Column 1 - Seller
Column 1 - Warehouse
Also the header should be in black color and the extracted details in red.

Please help me with my problem

 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Data;
using Excel = Microsoft.Office.Interop.Excel;
using Outlook = Microsoft.Office.Interop.Outlook;

namespace xlsm
{
    class New
    {
        static void Main(sting[] args)
        {
        sting st;
            long rCnt, cCnt;
            long rows = 0, columns = 0;

        Excel.Application xlApp;
        Excel.Workbook xlWorkBook;
        Excel.Worksheet xlWorkSheet;
        Excel.Range rng;

        xlApp = new Excel.Application();
        xlWorkBook = xlApp.Workbooks.Open(@"F:\Doc_Excel", 0, true, 5, "", "", true, Microsoft.Office.Interop.Excel.XlPlatform.xlWindows, "\t", false, false, 0, true, 1, 0);
        xlWorkSheet = (Excel.Worksheet)xlWorkBook.Worksheets["First Sheet"];


        rng = xlWorkSheet.UsedRange;
        rows = rng.Rows.Count;
        columns = rng.Columns.Count;

        List<Memo> lst = new List<Memo>();

        for (rCnt = 1; rCnt < rows; rCnt++)
        {
            for (cCnt = 1; cCnt < columns; cCnt++)
            {

                if ((rng.Cells[rCnt, cCnt] as Excel.rng).Value2 != null)
                {
                    st = (rng.Cells[rCnt, cCnt] as Excel.rng).Value2.Tosting();
                    if (st == "x")
                    {
                        Memo ms = new Memo();

                        ms.MemoName = (rng.Cells[rCnt, 1] as Excel.rng).Value2.Tosting();
                        ms.Type = (rng.Cells[rCnt, 2] as Excel.rng).Value2.Tosting();
                        ms.Ext = (rng.Cells[rCnt, 3] as Excel.rng).Value2.Tosting();
                        ms.Seller = (rng.Cells[rCnt, 4] as Excel.rng).Value2.Tosting();
                        ms.Warehouse = (rng.Cells[rCnt, 5] as Excel.rng).Value2.Tosting();
                        lst.Add(ms);

                    }
                }

            }
        }

        try
        {

            Outlook.Application oApp = new Outlook.Application();
            Outlook.MailItem oMsg = (Outlook.MailItem)oApp.CreateItem(Outlook.OlItemType.olMailItem);
            StringBuilder sb = new StringBuilder();
            sb.Append("<table>");
            foreach (var row in lst)
           {
            sb.Append("<tr>");
            sb.Append("<td>" + row.MemoName + "</td>");
            sb.Append("<td>" + row.Type + "</td>");
            sb.Append("<td>" + row.Ext + "</td>");
            sb.Append("<td>" + row.Seller + "</td>");
            sb.Append("<td>" + row.Warehouse + "</td>");
            sb.Append("</tr>");
           }
            sb.Append("</table>");
            oMsg.HTMLBody = sb.ToString();
            oMsg.Subject = "Memo contents as required.";
            Outlook.Recipients oRecims = (Outlook.Recipients)oMsg.Recipients;
            Outlook.Recipient oRecip = (Outlook.Recipient)oRecims.Add("[email protected]");
            oRecip.Resolve();
            oMsg.Send();

            oRecip = null;
            oRecims = null;
            oMsg = null;
            oApp = null;
        }
        catch (Exception ex)
        {
        }
        xlWorkBook.close(true, null, null);
        xlApp.Quit();

        Marshal.ReleaseComObject(xlWorkSheet);
        Marshal.ReleaseComObject(xlWorkBook);
        Marshal.ReleaseComObject(xlApp);
    }

}
public class Memo
{
    public string MemoName { get; set; }
    public string Type { get; set; }
    public string Ext { get; set; }
    public string Seller { get; set; }
    public string Warehouse { get; set; }
}