如何在双变量中设置空值 [英] How to paas a null value in double variable

问题描述

大家好，


如何在双变量中设置空值，例如


Double abc = null;
或Double abc =";


谢谢

mohd wasif

Hi All,


How to paas a null value in double variable e.g.


Double abc=null;
or Double abc="";


thanks

mohd wasif

推荐答案

如果要分配NULL，请使用Nullable Types.

例如:

Use Nullable Types if you want to assign NULL.

For example:

int? i = 10;
double? d1 = 3.14;
bool? flag = null;
char? letter = 'a';

有关Nullable Types的更多信息，请查看以下链接:
http://www.blackwasp.co.uk/CSharpNullableDataTypes.aspx [ http://www.codeguru. com/csharp/csharp/cs_syntax/operators/article.php/c10393/Using-Nullable-Types-in-C.htm [ http://msdn.microsoft.com/en-us/library/2cf62fcy.aspx [ ^ ]

For more information on Nullable Types look into following links:
http://www.blackwasp.co.uk/CSharpNullableDataTypes.aspx[^]
http://www.codeguru.com/csharp/csharp/cs_syntax/operators/article.php/c10393/Using-Nullable-Types-in-C.htm[^]
http://msdn.microsoft.com/en-us/library/2cf62fcy.aspx[^]

double是一个值类型.值类型实际上没有空值.但是您可以通过使用这种语法获得可为null的double.

double is a value type. value types dont really have null values. but you can have nullable double by using this syntax.

Nullable<Double> d = null;

这将起到双重作用.尝试使用它.只要记住可空类型是不可变的.但是由于您使用的是double，对您来说不会是一个大问题.

P.S.我刚才告诉你的简写是

this will work same as a double. try using it. Just remember nullable types are immutable. but since you are using double it wont be a big problem for you.

P.S. the shorthand of what i just told you is like

Double? d = null;

它的意思是一样的.只是第一个语法糖.

it means the same. just a syntactic sugar for the first one.

这篇关于如何在双变量中设置空值的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！