singSystem;usingSystem.Collections.Generic;usingSystem.Configuration;usingSystem.Data;usingSystem.Data.SqlClient;usingSystem.Linq;usingSystem.Text;usingSystem.Threading.Tasks;namespaceCarHailing.Base{///<summary>///数据库帮助类///</summary>publicclassSqlHelp{///<summary>///创建一个已打开的连接///</summary>///<returns></returns>privatestaticSqlConnectionCreateConn(){SqlConnectionconn=newSqlConnection(ConfigurationManager.ConnectionStrings["conn"].ConnectionString);conn.Open();returnconn;}///<summary>///执行sql语句，返回受影响的行数///</summary>///<paramname="sql"></param>///<returns></returns>publicstaticintExecuteNonQuery(stringsql){returnExecuteNonQuery(sql,null);}///<summary>///执行sql语句，返回受影响的行数///</summary>///<paramname="sql"></param>///<returns></returns>publicstaticintExecuteNonQuery(stringsql,SqlParameter[]ps){SqlConnectionconn=CreateConn();SqlCommandcmd=newSqlCommand(sql,conn);try{if(ps!=null){cmd.Parameters.AddRange(ps);}returncmd.ExecuteNonQuery();}catch(Exceptionex){return0;}finally{conn.Close();}}///<summary>///执行sql语句,返回一个结果表///</summary>///<paramname="sql"></param>///<returns></returns>publicstaticDataTableExecuteSelectDataTable(stringsql){returnExecuteSelectDataTable(sql,null);}///<summary>///执行sql语句,返回一个结果表///</summary>///<paramname="sql"></param>///<paramname="ps"></param>///<returns></returns>publicstaticDataTableExecuteSelectDataTable(stringsql,SqlParameter[]ps=null){SqlConnectionconn=CreateConn();SqlCommandcmd=newSqlCommand(sql,conn);try{if(ps!=null){cmd.Parameters.AddRange(ps);}//SqlDataAdaptersda=newSqlDataAdapter(cmd);SqlDataReaderread=cmd.ExecuteReader();DataTabletable=newDataTable();table.Load(read);//DataSetds=newDataSet();//sda.Fill(ds);returntable;}finally{conn.Close();}}///<summary>//////</summary>///<paramname="sql"></param>///<returns></returns>decimalpublicstaticDataTableExecuteSelectPageDataTable(stringsql,refSqlParameter[]ps){SqlConnectionconn=CreateConn();SqlCommandcmd=newSqlCommand(sql,conn);cmd.CommandType=CommandType.StoredProcedure;try{cmd.Parameters.AddRange(ps);SqlDataAdaptersda=newSqlDataAdapter(cmd);DataSetds=newDataSet();sda.Fill(ds);returnds.Tables[0];}catch(SqlExceptionex){throwex;}finally{conn.Close();}}//publicstaticSqlDataReaderExecuteReader(stringcmdText,CommandTypecmdType,paramsSqlParameter[]cmdParms)//{//SqlCommandcmd=newSqlCommand();//SqlConnectionconn=CreateConn();//try//{//ProCommand(cmd,conn,cmdText,cmdType,cmdParms);//SqlDataReaderrdr=cmd.ExecuteReader(CommandBehavior.CloseConnection);////cmd.Parameters.Clear();//放到这里，返回参数会被清空。//returnrdr;//}//catch//{//conn.Close();//throw;//}//}///<summary>///分页读取数据///</summary>///<paramname="query">select查询语句</param>///<paramname="pageSize">每页显示数据数</param>///<paramname="PageIndex">当前页码</param>///<paramname="dt">存储数据的DataTable实例</param>publicstaticvoidPageDataTable(stringquery,intpageSize,intPageIndex,DataTabledt){//读取数据的开始索引longstartIndex=(PageIndex-1)*pageSize;//读取数据的结束索引longendIndex=PageIndex*pageSize-1;//DataReader读取的当前数据行的索引longreadToIndex=-1;using(SqlConnectionconn=CreateConn()){SqlCommandcmd=newSqlCommand(query,conn);//conn.Open();SqlDataReaderdr=cmd.ExecuteReader();//数据源中的列数intcols=dr.VisibleFieldCount;//构造DataTable结构for(inti=0;i<cols;i++){dt.Columns.Add(newDataColumn(dr.GetName(i),dr.GetFieldType(i)));}//读取数据，将数据一行一行添加到DataTablewhile(dr.Read()){readToIndex++;//当DataReader指针在开始索引和结束索引闭区间时才读取数据构造DataRow//并添加到DataTableif(readToIndex>=startIndex&&readToIndex<=endIndex){DataRowrow=dt.NewRow();for(inti=0;i<cols;i++){row[i]=dr[i];}dt.Rows.Add(row);}}dr.Close();}}}}
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