C#其他类型转字符串! - V2EX
hoperce

C#其他类型转字符串!

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  •   hoperce Jun 1, 2012 4171 views
    This topic created in 5093 days ago, the information mentioned may be changed or developed.
    加空字符串("") 和 ToString() 和 (string) 有什么区别和代价么?
    6 replies    1970-01-01 08:00:00 +08:00
    avatasia
        1
    avatasia  
       Jun 1, 2012   1
    你是要说string s = 10 + ""; 这样子算加空字符串?还是什么?
    3.5还是4.0之后,int直接支持和string相加, 默认转型了,效率上有点问题。
    ToString()用的比较多, (string)很少用到,不推荐使用。
    里面涉及到装箱拆箱的基础知识,string.format()这个效率最高,具体你可以看看陆敏技的书或者CLR via C#
    acterce
        2
    acterce  
       Jun 1, 2012
    呔! 秃驴
    caoyue
        3
    caoyue  
       Jun 1, 2012   1
    加空字符串不推荐。虽然同样是由 CLR 自动调用了 Tostring() ,但字符串的操作会生成两个副本等待 GC 回收。
    一般是用 Tostring() 或是 Convert.Tostring() ,区别是 Object 为 Null 的时候前者会异常而后者会返回空字符串。
    强制转换要求对象运行时类型是 string ,否则就会异常,不推荐使用。
    hoperce
        4
    hoperce  
    OP
       Jun 1, 2012
    @acterce 额。
    hoperce
        5
    hoperce  
    OP
       Jun 1, 2012
    @caoyue 但是ToString()在对象为空的时候会出现异常!Convert.ToString()表示没用过!
    hoperce
        6
    hoperce  
    OP
       Jun 1, 2012
    @avatasia 3.5和4.0都有。 string s=object+""这样的。
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