这个using是什么意思?
这是.net的那套工具所带的网上书店的代码中的一段,
using (Books bookDataAccess = new Books())
{
BookData retVal = null;
switch (searchType)
{
case BookData.SearchTypeEnum.Author:
retVal = bookDataAccess.GetBooksByAuthor(searchText);
break;
case BookData.SearchTypeEnum.ISBN:
retVal = bookDataAccess.GetBooksByISBN(searchText);
break;
case BookData.SearchTypeEnum.Subject:
retVal = bookDataAccess.GetBooksBySubject(searchText);
break;
case BookData.SearchTypeEnum.Title:
retVal = bookDataAccess.GetBooksByTitle(searchText);
break;
default:
ApplicationAssert.Check(false, string.Format("searchType {0} is not valid", searchType.ToString()), ApplicationAssert.LineNumber);
break;
}
return retVal;
}
这里的using和一般使用的方式不太一样,那位大侠告诉我在这里面为什么要使用using。