Exporting from C#

    /// <summary>
    /// Web Utility Function For Exporting Data Set to Specified Format
    /// </summary>
    /// <param name="dsResults">Result Data Set</param>
    /// <param name="enExport">Export Enum Values</param>
    /// <param name="strColDelim">Column Delimiter value</param>
    /// <param name="strRowDelim"></param>
    /// <param name="strFileName"></param>
    public static void ExportDataSet(DataSet dsResults , ExportFormat enExport,string strColDelim, string strRowDelim, string strFileName)
    {
        DataGrid dgExport = new DataGrid();      
        dgExport.AllowPaging =false;
        dgExport.DataSource =dsResults;
        dsResults.DataSetName ="WebERP";
        dgExport.DataMember =  dsResults.Tables[0].TableName;
        dgExport.DataBind();          
        System.Web.HttpContext.Current.Response.Clear();          
        System.Web.HttpContext.Current.Response.Buffer= true;
        System.Web.HttpContext.Current.Response.ContentEncoding = Encoding.UTF8;
        System.Web.HttpContext.Current.Response.Charset = "";
        System.Web.HttpContext.Current.Response.AddHeader("Content-Disposition", "attachment; filename=" +strFileName );
        switch(enExport.ToString().ToLower())
        {
            case "xls":
            {
                System.Web.HttpContext.Current.Response.ContentType = "application/vnd.ms-excel";                                      
                System.IO.StringWriter oStringWriter = new System.IO.StringWriter();                                      
                System.Web.UI.HtmlTextWriter oHtmlTextWriter = new System.Web.UI.HtmlTextWriter(oStringWriter);
                dgExport.RenderControl(oHtmlTextWriter);
                System.Web.HttpContext.Current.Response.Write(oStringWriter.ToString());
                break;
            }
            case "custom":
            {
                string strText;                          
                System.Web.HttpContext.Current.Response.ContentType = "text/txt";                                                  
                System.IO.StringWriter oStringWriter = new System.IO.StringWriter();                  
                System.Web.UI.HtmlTextWriter oHtmlTextWriter = new System.Web.UI.HtmlTextWriter(oStringWriter);                  
                dgExport.RenderControl(oHtmlTextWriter);
                strText = oStringWriter.ToString();                  
                strText = ParseToDelim(strText ,strRowDelim,strColDelim);
                System.Web.HttpContext.Current.Response.Write(strText);
                break;
            }
            case "csv":
            {
                string strText;      
                strRowDelim = System.Environment.NewLine;
                strColDelim = ",";
                System.Web.HttpContext.Current.Response.ContentType = "text/txt";
                System.IO.StringWriter oStringWriter = new System.IO.StringWriter();                  
                System.Web.UI.HtmlTextWriter oHtmlTextWriter = new System.Web.UI.HtmlTextWriter(oStringWriter);                                      
                dgExport.RenderControl(oHtmlTextWriter);
                strText = oStringWriter.ToString();                  
                strText = ParseToDelim(strText ,strRowDelim,strColDelim);
                System.Web.HttpContext.Current.Response.Write(strText);
                break;
            }          
            case "tsv":
            {
                string strText;      
                strRowDelim = System.Environment.NewLine;
                strColDelim = "\t";
                System.Web.HttpContext.Current.Response.ContentType = "text/txt";                                                  
                System.IO.StringWriter oStringWriter = new System.IO.StringWriter();                  
                System.Web.UI.HtmlTextWriter oHtmlTextWriter = new System.Web.UI.HtmlTextWriter(oStringWriter);                                      
                dgExport.RenderControl(oHtmlTextWriter);
                strText = oStringWriter.ToString();                  
                strText = ParseToDelim(strText ,strRowDelim,strColDelim);
                System.Web.HttpContext.Current.Response.Write(strText);
                break;
            }
            case "xml":
            {
                System.Web.HttpContext.Current.Response.ContentType = "text/xml";                  
                System.Web.HttpContext.Current.Response.Write(dsResults.GetXml());                                      
                break;
            }
            case "htm":
            {                  
                System.Web.HttpContext.Current.Response.ContentType = "text/html";
                System.IO.StringWriter oStringWriter = new System.IO.StringWriter();                  
                System.Web.UI.HtmlTextWriter oHtmlTextWriter = new System.Web.UI.HtmlTextWriter(oStringWriter);
                dgExport.RenderControl(oHtmlTextWriter);                  
                System.Web.HttpContext.Current.Response.Write(oStringWriter.ToString());                  
                break;
            }
        }
    }

}

#region "Export To a Delim Format"
public static string ParseToDelim(string strText, string  strRowDelim , string strColDelim)
{
    Regex objReg = new Regex(@"(>\s+<)",RegexOptions.IgnoreCase);                  
    strText = objReg.Replace(strText,"><");
    strText = strText.Replace(System.Environment.NewLine,"");
    strText = strText.Replace("</td></tr><tr><td>",strRowDelim);
    strText = strText.Replace("</td><td>",strColDelim);
    objReg = new Regex(@"<[^>]*>",RegexOptions.IgnoreCase);                  
    strText = objReg.Replace(strText,"");              
    strText = System.Web.HttpUtility.HtmlDecode(strText);
    return strText;
}
#endregion
      
public enum ExportFormat
{
    XML,
    XLS,
    HTML,
    CSV,
    CUSTOM,
    TSV  
}