kdxd

private void toolExcel_Click(object sender, EventArgs e)
        {

            Microsoft.Reporting.WinForms.Warning[] Warnings;
            string[] strStreamIds;
            string strMimeType;
            string strEncoding;
            string strFileNameExtension;

            byte[] bytes = this.rptViewer.LocalReport.Render("Excel", null, out strMimeType, out strEncoding, out strFileNameExtension, out strStreamIds, out Warnings);

            //string strFilePath = @"D:\" + this.GetTimeStamp() + ".xls";

　　　　　 SaveFileDialog Dialog = new SaveFileDialog();
              Dialog.Filter = "*.xls|*.*";
              Dialog.ShowDialog();

              string strFilePath = Dialog.FileName;

            using (System.IO.FileStream fs = new FileStream(strFilePath, FileMode.Create))
            {
                fs.Write(bytes, 0, bytes.Length);
            }

            if (Pub.WinForm.Msg.Question("报表打印： \r\n    成功导出Excel文件！" + strFilePath + "\r\n    要现在打开文件" + strFilePath + "吗？") == DialogResult.Yes)
            {
                System.Diagnostics.Process.Start(strFilePath);
            }

        }

from http://www.cnblogs.com/waxdoll/archive/2006/03/03/342435.html