vb.net 需要检查空字符串，visual basic
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Need to check for empty string, visual basic
提问by safary
Can someone help me to write a code that checks if string is empty and returns null if its true?
有人可以帮我写一个代码来检查字符串是否为空，如果为真则返回 null 吗？
I have this now:
我现在有这个：
If(Not IsNothing(role.ROLE_DESC),role.ROLE_DESC.ToString(),Nothing)
But it only checks if role_desc is null, but I need to also check if its value is not an empty string and if so, then return null.
但它只检查 role_desc 是否为空，但我还需要检查它的值是否不是空字符串，如果是，则返回 null。
回答by Cal.B
What taquion said, or IsNullOrWhiteSpace.
Looks like:
什么taquion说，或IsNullOrWhiteSpace。好像：
If TypeOf role.ROLE_DESC Is String AndAlso String.IsNullOrEmpty(role.ROLE_DESC) OrElse String.IsNullOrWhiteSpace(role.ROLE_DESC) Then
'It is empty or whitespace
Else
'it isn't empty or whitespace
End If
