从数据库读取数据到datatable，返回值类型是表。使用SqlDataAdapter方法，具体实例如下：
/// <summary> /// 执行SQL语句，插入一条数据 /// </summary> ///<return>datatable</return> public DataTable ExecuteSql(string SQLString) { //读取配置文件数据库连接信息 //<add key="ConnStr" value="server=ip;database=databasename;uid=usr;pwd=pwd;" /> using (SqlConnection connection = new SqlConnection(ConfigurationManager.AppSettings["ConnStr"])) { using (SqlCommand cmd = new SqlCommand(SQLString, connection)) { try { connection.Open(); DataTable dt = new DataTable(); cmd.CommandTimeout = 60; SqlDataAdapter sda = new SqlDataAdapter(cmd); sda.Fill(dt); cmd.Dispose(); connection.Close(); return dt; } catch (System.Data.SqlClient.SqlException E) { connection.Close(); throw new Exception(E.Message); } } } }