一个语句的问题
Dim data As [String] = Nothing 和
Dim data As String = Nothing
有什么不同？

[解决办法]
方括号的作用是当定义的类型或变量名或名称空间与VB的保留关键字发生冲时，用于标识方括号内的内容为非关键字.
比如常见的Dim ass As [Assembly],如果不带方括号,Assembly为一个关键字，而不是命名类型.
[解决办法]
恩恩，楼上说的对：

Public Class Form1

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim data As [String]
Dim data1 As String

data = New [String]
data1 = New String(Nothing)

MsgBox(data.haha)
MsgBox(data1)
End Sub
End Class

Public Class [String]
Public Function haha() As String
Return "haha "
End Function
End Class