Posted on 2007-02-12 15:53
dennis 閱讀(740)
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C#歷程
C#的using語(yǔ)句設(shè)計(jì)的蠻貼心，比java的import有趣一點(diǎn)。轉(zhuǎn)一篇文章.
C#中的using除了作為命名空間指示符(using System)，類型的別名指示符(using Dos=System.Console)，還有資源管理的語(yǔ)句功能：
using (R r1 = new R ()) {
? ?r1.F();
}
在C#中被翻譯為：
R?r1?=?new?R();
try?{
???r1.F();
}
finally?{
???if?(r1?!=?null)?((IDisposable)r1).Dispose();
}
r1當(dāng)然要支持Dispose()方法了
再來(lái)一個(gè)例子：
#?MyObject.cs
using
?System;
?
namespace
?MyProjects
{
????
public
?
class
?MyObject?:?IDisposable
????{
????????
public
?MyObject()
????????{
????????}
?
????????
public
?
void
?Dispose?(?)
????????{
????????????
//
?Dispose
????????????Console.WriteLine?(?
"
Disposed
"
?)?;
????????????
//
?
????????}
????}
}
?
#?Class1.cs
using
?System;
?
namespace
?MyProjects
{
?????
public
?
class
?Class1
?????{
?????????
public
?Class1()
?????????{
?????????}
?
?????????
public
?
static
?
void
?Main?(?
string
[]?args?)
?????????{
??????????????
using
?(?MyObject?myObject?
=
?
new
?MyObject?(?)?)
??????????????{
???????????????????Console.WriteLine?(?
"
quit
"
?)?;
??????????????}
?????????}
?????}
}
?
使用using會(huì)自動(dòng)調(diào)用MyObject的Dispose方法.