一个筛选的正则表达式，记性太差了，记下来吧！

 

            const string strHtml = @"
<table width=""230"" border=""0"" cellpadding=""0"" cellspacing=""1"" bgcolor=""#a5abb7""  height=""285"" >
             
              <tr>
              <td width=""78"" height=""34"" align=""center"" valign=""middle"" bgcolor=""#FFFFFF"" class=""font_lan"">abc</td>
              <td width=""74"" height=""34"" valign=""middle"" align=""center"" valign=""middle"" bgcolor=""#FFFFFF"" class=""font_lan"">4491</td>
              <td width=""74"" height=""34"" valign=""middle"" align=""center"" valign=""middle"" bgcolor=""#FFFFFF"" class=""font_lan"">4745</td>
             </tr>

              <tr>
              <td width=""78"" height=""34"" align=""center"" valign=""middle"" bgcolor=""#FFFFFF"" class=""font_lan"">afe</td>
              <td width=""74"" height=""34"" valign=""middle"" align=""center"" valign=""middle"" bgcolor=""#FFFFFF"" class=""font_lan"">4491</td>
              <td width=""74"" height=""34"" valign=""middle"" align=""center"" valign=""middle"" bgcolor=""#FFFFFF"" class=""font_lan"">1234</td>
             </tr>
</table>";

            MatchCollection m = Regex.Matches(strHtml, @"(?<=<tds+[^>]*>).*?(?=</td>)", RegexOptions.IgnoreCase);

            string strResult = "";

            for (int i = 0; i < m.Count; i++)
            ...{ 
                strResult += m[i].Value + Environment.NewLine;
            }

            MessageBox.Show(strResult);