Hi,
Try this..
Example :
string Subject = "Hai";
string Priority = "First";
string status = "Yes";
string linkuser = "http://www.codeproject.com/";
string mailbodyUser = BodydetailsUser + "<br><br><br>" + "<body style='margin: 0; padding: 0;'> <table align='center' cellpadding='5' cellspacing='0' width='600px' style='border: 1px solid #DDD;border-collapse: collapse;'><tr><td colspan='2' bgcolor='#dddddd' style='border: 1px solid #DDD;border-collapse: collapse;'>List Items</td></tr><tr><td style='border: 1px solid #DDD;border-collapse: collapse;'>Subject</td><td style='border: 1px solid #DDD;border-collapse: collapse;'> " + Subject + "</td></tr><tr><td style='border: 1px solid #DDD;border-collapse: collapse;'>Priority </td><td style='border: 1px solid #DDD;border-collapse: collapse;'>" + Priority + "</td></tr><tr><td style='border: 1px solid #DDD;border-collapse: collapse;'>Status</td><td style='border: 1px solid #DDD;border-collapse: collapse;'> " + status + "</td></tr></table></body>" + "<br/><br/><br/>You can replay on this ticket at <a href= " + linkuser + ">Click Here</a>";
message.Body = mailbodyUser;