Visual Basic .NET空/空字符串的区别？

Question

我想区分NULL和"".

如果String为NULL或"",如何使用if语句确定？

Answer 1

Nothing当字符串变量没有实例时,它完全引用,而""当字符串变量具有它引用的内容时,它是一个空字符串.

为了区分,您可以提出以下条件:

Dim s As String

If s Is Nothing Then 'It means it is Nothing

End If

If s = "" Then 'It means it points to some instance whose value is empty string

End If

VB.Net也有String.Empty相当于"":

If s = String.Empty Then

End If