vb.net – VB将字符串设置为空

参见英文答案 > Nothing = String.Empty (Why are these equal?)4个
> Difference between C# and VB.Net string comparison2个
当我预期它返回FALSE时,下面的代码返回TRUE.

为什么它返回TRUE？我希望没有什么可以将字符串的值设置为null,而不是为空(根据msdn)

CodeingGround sample

Module VBModule

    Sub Main()
        dim x as String
        x = nothing
        console.writeline(x = string.Empty)
    End Sub

End Module

Nothing (Visual Basic)

Represents the default value of any data type. For reference types,
the default value is the null reference.

***编辑****
Nothing = String.Empty (Why are these equal?)

VB.net中没有任何内容是类型的默认值.语言规范在2.4.7节中说明：

Nothing is a special literal; it does not have a type and is
convertible to all types in the type system,including type
parameters. When converted to a particular type,it is the equivalent
of the default value of that type.

因此,当您对String.Empty进行测试时,Nothing将转换为长度为0的字符串.Is运算符应该用于测试Nothing,而String.Empty.Equals(Nothing)也将返回false.

那时评论,

when converted to a particular type,it is the equivalent of the
default value of that type.

字符串的默认值为null.我不明白为什么这个答案被接受了.