Ado.net 数据库读取文件

string connStr = ConfigurationManager.ConnectionStrings["connStr"].ConnectionString;
            using(SqlConnection conn = new SqlConnection(connStr))
            {
                using(SqlDataAdapter adapter = new SqlDataAdapter("select * from userInfo", conn))
                {
                    DataTable da = new DataTable();
                    adapter.Fill(da);
                    if (da.Rows.Count > 0)
                    {
                        StringBuilder sb = new StringBuilder();
                        foreach (DataRow row in da.Rows)
                        {
                            sb.AppendFormat("<tr><td>{0}</td><td>{1}</td><td>{2}</td></tr>", row["ID"].ToString(), row["Name"].ToString(), row["UserName"].ToString());
                        }

                        //读取模板文件，替换占位符
                        string filePath = context.Request.MapPath("UserInfoList.html");
                        string fileContent = File.ReadAllText(filePath);
                        fileContent = fileContent.Replace("要替换的占位符", sb.ToString());
                        context.Response.Write(fileContent);
                    }
                    else
                    {
                        context.Response.Write("暂无数据");
                    }
                }
            }