#T#很多開(kāi)發(fā)語(yǔ)言都支持異步通信，在ADO.NET中支持異步處理的提供程序有System.Data.SqlClient在針對(duì)大批量數(shù)據(jù)插入過(guò)更新時(shí)，使用ADO.NET數(shù)據(jù)異步處理方法可以不用等待多有數(shù)據(jù)更新完畢才能操作或者進(jìn)行下步處理，改善了用戶體驗(yàn)SqlCommand對(duì)象方法如下：

ADO.NET數(shù)據(jù)異步處理
◆BeginExecuteNonQueryEndExecuteNonQuery
◆BeginExecuteXmlReaderEndExecuteXmlReader
◆BeginExecuteReaderEndExecuteReader
◆begin前綴的方法傳入?yún)?shù)，end前綴的方法返回輸出參數(shù)和返回值
◆begin前綴方法返回的是IAsyncResult用于追蹤一步方法的執(zhí)行狀態(tài)
◆IAsyncResult.AsnycState用戶自定義的狀態(tài)對(duì)象
◆IAsyncResult.AsnycWaitHandle呼叫代碼的等待形式，是等其中的一個(gè)異步方法完成還是全部完成
◆IAsyncResult.CompletedSynchronously獲取所有異步方法是否同時(shí)完成
◆IAsyncResult.Iscompleted是否執(zhí)行完畢，可以根據(jù)此屬性進(jìn)行下部動(dòng)作

在連接字符串中加入"async＝true"如果所有的命令都是同步的建議在連接字符串中顯施加入，"async＝false"如果有一部分命令是異步執(zhí)行，又有一部分是同步同步執(zhí)行，建議分別建立兩個(gè)連接對(duì)象，如果"async＝true"時(shí)，也可以執(zhí)行同步命令，但是會(huì)損失一些資源

/**/////obtainconnectionstringsfromconfigurationfilesor  
////similarfacility  
////NOTE:theseconnectionstringshavetoinclude"async=true",for  
////example:  
////"server=myserver;database=mydb;integratedsecurity=true;async=true"  
//stringconnstrAccouting=GetConnString("accounting");  
//stringconnstrHR=GetConnString("humanresources");  
/**/////definetwoconnectionobjects,oneforeachdatabase  
//using(SqlConnectionconnAcc=newSqlConnection(connstrAccounting))  
//using(SqlConnectionconnHumanRes=newSqlConnection(connstrHR))  
//{  
////openthefirstconnection  
//connAcc.Open();  
////starttheexecutionofthefirstquerycontainedinthe  
////"employee_info"stored-procedure  
//SqlCommandcmdAcc=newSqlCommand("employee_info",connAcc);  
//cmdAcc.CommandType=CommandType.StoredProcedure;  
//cmdAcc.Parameters.AddWithValue("@empl_id",employee_id);  
//IAsyncResultarAcc=cmdAcc.BeginExecuteReader();  
////atthispoint,the"employee_info"stored-procisexecutingon  
////theserver,andthisthreadisrunningatthesametime  
////nowopenthesecondconnection  
//connHumanRes.Open();  
////starttheexecutionofthesecondstored-procagainst  
////thehuman-resourcesserver  
//SqlCommandcmdHumanRes=newSqlCommand("employee_hrinfo",  
//connHumanRes);  
//cmdHumanRes.Parameters.AddWithValue("@empl_id",employee_id);  
//IAsyncResultarHumanRes=cmdHumanRes.BeginExecuteReader();  
////nowbothqueriesarerunningatthesametime  
////atthispoint;moreworkcanbedonefromthisthread,orwe  
////cansimplywaituntilbothcommandsfinish-inourcasewe'll  
////wait  
//SqlDataReaderdrAcc=cmdAcc.EndExecuteReader(arAcc);  
//SqlDataReaderdrHumanRes=cmdHumanRes.EndExecuteReader(arHumanRes);  
////nowwecanrendertheresults,forexample,bindthereaderstoanASP.NET  
////webcontrol,orscanthereaderanddrawtheinformationina  
////WebFormsform.  
//}  
 
stringcustid="ALFKI";  
stringorderid="10643";  
 
//NOTE:connectionstringsdenotedby"connstring"havetoinclude  
//"async=true",forexample:  
stringconnstring="server=(local);database=northwind;integratedsecurity=true;async=true";  
//we'llusethreeconnectionsforthis  
using(SqlConnectionc1=newSqlConnection(connstring))  
using(SqlConnectionc2=newSqlConnection(connstring))  
using(SqlConnectionc3=newSqlConnection(connstring))  
{  
//getcustomerinfo  
c1.Open();  
SqlCommandcmd1=newSqlCommand(  
"SELECTCustomerID,CompanyName,ContactNameFROMCustomersWHERECustomerID=@id",c1);  
cmd1.Parameters.Add("@id",SqlDbType.Char,5).Value=custid;  
IAsyncResultarCustomer=cmd1.BeginExecuteReader();  
//getorders  
c2.Open();  
SqlCommandcmd2=newSqlCommand("SELECT*FROMOrdersWHERECustomerID=@id",c2);  
cmd2.Parameters.Add("@id",SqlDbType.Char,5).Value=custid;  
IAsyncResultarOrders=cmd2.BeginExecuteReader();  
//getorderdetailifuserpickedanorder  
IAsyncResultarDetails=null;  
SqlCommandcmd3=null;  
if(null!=orderid)  
{  
c3.Open();  
cmd3=newSqlCommand("SELECT*FROM[OrderDetails]WHEREOrderID=@id",c3);  
cmd3.Parameters.Add("@id",SqlDbType.Int).Value=int.Parse(orderid);  
arDetails=cmd3.BeginExecuteReader();  
}  
//buildthewaithandlearrayforWaitForMultipleObjects  
WaitHandle[]handles=newWaitHandle[null==arDetails?2:3];  
handles[0]=arCustomer.AsyncWaitHandle;  
handles[1]=arOrders.AsyncWaitHandle;  
if(null!=arDetails)  
handles[2]=arDetails.AsyncWaitHandle;  
//waitforcommandstocompleteandrenderpagecontrolsaswe  
//getdataback  
SqlDataReaderr;  
DataTabledt;  
for(intresults=(null==arDetails)?1:0;results<3;results++)  
{  
//waitforanyhandle,thenprocessresultsastheycome  
intindex=WaitHandle.WaitAny(handles,5000,false);//5secs  
if(WaitHandle.WaitTimeout==index)  
thrownewException("Timeout");  
switch(index)  
{  
case0://customerqueryisready  
r=cmd1.EndExecuteReader(arCustomer);  
if(!r.Read())  
continue;  
lblCustomerID.Text=r.GetString(0);  
lblCompanyName.Text=r.GetString(1);  
lblContact.Text=r.GetString(2);  
r.Close();  
break;  
case1://ordersqueryisready  
r=cmd2.EndExecuteReader(arOrders);  
dt=newDataTable();  
dt.Load(r);  
dgOrders.DataSource=dt;//data-bindtotheordersgrid  
dgOrders.Refresh();  
r.Close();  
break;  
case2://detailsqueryisready  
r=cmd3.EndExecuteReader(arDetails);  
dt=newDataTable();  
dt.Load(r);  
dgDetails.DataSource=dt;//data-bindtothedetailsgrid  
dgDetails.Refresh();  
r.Close();  
break;  
 
}  
}  
} 

以上就是ADO.NET數(shù)據(jù)異步處理用戶體驗(yàn)的一個(gè)解決方案，大家快試試。