C # use the data connection pool for the general dbhelper class

In web. config

<connectionStrings><add name="dh_web" connectionString="Data Source=xxx.com;Initial Catalog=xx_db;User ID=xx;Password=**;            pooling=true;max pool size=200" providerName="System.Data.SqlClient"/></connectionStrings>

Public class dbhelper {Private Static string connectionstring = configurationmanager. connectionstrings ["dh_web"]. connectionstring; // The public static int executecommand (string safesql) {using (sqlconnection connection = new sqlconnection (connectionstring) {connection. open (); sqlcommand cmd = new sqlcommand (safesql, connection); Return cmd. executenonquery () ;}}// public static int executecommand (string SQL, Params sqlparameter [] values) {using (sqlconnection connection = new sqlconnection (connectionstring )) {connection. open (); sqlcommand cmd = new sqlcommand (SQL, connection); cmd. parameters. addrange (values); Return cmd. executenonquery () ;}} public static int getscalar (string safesql) {using (sqlconnection connection = new sqlconnection (connectionstring) {connection. open (); sqlcommand cmd = new sqlcommand (safesql, connection); Return convert. toint32 (CMD. executescalar () ;}} public static int getscalar (string SQL, Params sqlparameter [] values) {using (sqlconnection connection = new sqlconnection (connectionstring) {connection. open (); sqlcommand cmd = new sqlcommand (SQL, connection); cmd. parameters. addrange (values); Return convert. toint32 (CMD. executescalar () ;}} public static sqldatareader getreader (string safesql) {sqlconnection connection = new sqlconnection (connectionstring); connection. open (); sqlcommand cmd = new sqlcommand (safesql, connection); Return cmd. executereader (commandbehavior. closeconnection);} public static sqldatareader getreader (string SQL, Params sqlparameter [] values) {sqlconnection connection = new sqlconnection (connectionstring); connection. open (); sqlcommand cmd = new sqlcommand (SQL, connection); cmd. parameters. addrange (values); Return cmd. executereader (commandbehavior. closeconnection);} public static datatable getdataset (string safesql) {using (sqlconnection connection = new sqlconnection (connectionstring) {dataset DS = new dataset (); sqlcommand cmd = new sqlcommand (safesql, connection); sqldataadapter da = new sqldataadapter (CMD); DA. fill (DS); Return Ds. tables [0] ;}} public static datatable getdataset (string SQL, Params sqlparameter [] values) {using (sqlconnection connection = new sqlconnection (connectionstring )) {dataset DS = new dataset (); sqlcommand cmd = new sqlcommand (SQL, connection); cmd. parameters. addrange (values); sqldataadapter da = new sqldataadapter (CMD); DA. fill (DS); Return Ds. tables [0] ;}}

Note:

Commandbehavior. closeconnection solves the problem that the database connection cannot be effectively closed when the stream reads data. commandbehavior is used when a xxxdatareader object is generated. closeconnection, the database connection will be automatically closed when the xxxdatareader object is closed.