净 - 投或转换装箱字节？，短？或INT？为int？ [英] .Net - Cast or convert a boxed byte?, short? or int? to int?

问题描述

如果我有一个对象引用，引用字节？，短？或诠释？，有没有办法无条件地投或转换的对象引用为int？无需编写单独的code每个案例？

例如：

 字节？ aByte = 42; // ..或aByte = NULL
object对象= aByte;
// ...
VAR ANINT =（INT？）anObject //正如预期的那样，无法正常工作
 

解决方案

我会使用<一个href="http://msdn.microsoft.com/en-us/library/23511zys.aspx"><$c$c>Convert.ToInt32(object):

 对象o = ...; // 拳击...
诠释？ X = O == NULL？ （INT？）空：Convert.ToInt32（O）;
 

请注意，当你框中诠释？，短？或字节？，你总是结束了一个空引用或盒装不可为空值 - 有没有这样的东西作为一个盒装空值这样

Convert.ToInt32 将适用于所有你所提到的盒装类型 - 尽管它会的也的东西像一个字符串作品42 等那是一个问题吗？

If I have an object reference that references a byte?, short? or int?, is there a way to unconditionally cast or convert that object reference to int? without writing separate code for each case?

For example:

byte? aByte = 42; // .. or aByte = null
object anObject = aByte;
//...
var anInt = (int?)anObject //As expected, doesn't work

解决方案

I'd use Convert.ToInt32(object):

object o = ...; // Boxing...
int? x = o == null ? (int?) null : Convert.ToInt32(o);

Note that when you box an int?, short? or byte?, you always end up with a null reference or a boxed non-nullable value - there's no such thing as a "boxed nullable value" as such.

Convert.ToInt32 will work for all the boxed types you've mentioned - although it would also work for things like a string "42" etc. Is that a problem?

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