网上转载……

//上传文件
            string filename = FileUpload1.FileName;
            string path = Server.MapPath("c:\\123\\" + filename);
            FileUpload1.SaveAs(path);
        

            string strConn = GetExcelConnString(path);
            OleDbConnection conn = new OleDbConnection(strConn);
            try
            {
                conn.Open();
            }
            catch (Exception ex)
            {
                //ShowClientJS("ShowInfo(\"错误：" + ex.Message + "\",1,5000);", this);
                return;
            }

//判断工作表个数
            DataTable dtTblNames = conn.GetSchema("Tables");
            if (dtTblNames.Rows.Count > 1)
            {
                conn.Close();
                //ShowClientJS("ShowInfo('导入失败：只允许1个工作表，当前有：" + dtTblNames.Rows.Count.ToString() + "',1,5000);", this);
                return;
            }
//只处理第一个工作表
            string tblName = dtTblNames.Rows[0]["Table_Name"].ToString();
            hidTableName.Value = tblName;
            OleDbCommand cmd = new OleDbCommand();
            cmd.Connection = conn;
            cmd.CommandText = "select * from [" + tblName + "]";
            OleDbDataAdapter da = new OleDbDataAdapter(cmd);
            DataTable dt = new DataTable();
            try
            {
                da.Fill(dt);
            }
            catch (Exception ex)
            {
                //ShowClientJS("ShowInfo(\"预览时发生错误：" + ex.Message + "\",1,5000);", this);
            }
            finally
            {
                conn.Close();
            }
//显示数据
            GridView1.DataSource = dt;
            GridView1.DataBind();