在实体类中有个属性如下,但是数据类型后面加了个问号,之前没遇到过public class Model(){ private int? _number; public int? Number
{
set{ _number=value;}
get{return _number;}
}}
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许å°ç©ºå¼(null)åint32çæ°æ®ç±»åä¸èµ·ä½¿ç¨ãåªéè¦ä½¿ç¨å¦ä¸ç³æå³å¯: int32? customerid æè
Nullable<Int32> customerid. è¿æ ·çè¯ï¼ä½ å°±å¯ä»¥éæè¿è¡ç©ºå¼æä½(null)æ¯å¦: int32? customerid customerid = null; è¿æ ·æ¯ä¸æ¯æ¯c#1.1çè¯æ³è¦æ¹ä¾¿?
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