????????????C# using???????using???????.NET?????????????????????λ???????????????????????????
????C# using????????MSDN???????????????????
????1?????????????2????????????????????????3?????using???
????1???????????????????????????????????????????????????????????????????
???????????????????????????usingSystem.Text;
????2????????????????????????
??????????cs?????????????????????Щ?????????????????????????????????????????using????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????using????????????

 

usingSystem;
usingaClass=NameSpace1.MyClass;
usingbClass=NameSpace2.MyClass;
......
//??÷??
aClassmy1=newaClass();
Console.WriteLine(my1);
bClassmy2=newbClass();
Console.WriteLine(my2);

????3?????using????????????Χ?????Χ????????????(?????????????????IDisposable???)???書???try??catch??Finally????????
????????:

 

using(SqlConnectioncn=newSqlConnection(SqlConnectionString)){......}//?????????
using(SqlDataReaderdr=db.GetDataReader(sql)){......}//DataReader
PS??????SqlConnection??SqlDataReader????????????IDisposable????????????д??????????????????IDisposable???????磺
using(Employeeemp=newEmployee(userCode))
{
......
}