VB Structure其中一个参数赋值后其余参数值变成一样了.为什么?

Public Class Form1

Public Structure MMLCHILDSEL
        Public Index() As String
        Public paraIndex() As String
        Public paraName() As String
        Public paraRange(,) As String
    End Structure

    Dim paraRecord As MMLCHILDSEL


    Sub test()

        Dim a(100) As String
        paraRecord.paraIndex = a
        paraRecord.Index = a
        paraRecord.paraName = a

        paraRecord.Index(0) = "0"
        paraRecord.paraIndex(0) = "1"
        paraRecord.paraName(0) = "value"
        MsgBox(paraRecord.Index(0))
        MsgBox(paraRecord.paraIndex(0))
        MsgBox(paraRecord.paraName(0))
    End Sub

End Class

        paraRecord.paraIndex = a
        paraRecord.Index = a
        paraRecord.paraName = a

        paraRecord.Index(0) = "0"               '相当于a(0)="0"
        paraRecord.paraIndex(0) = "1"           '相当于a(0)="1"
        paraRecord.paraName(0) = "value"        '相当于a(0)="value"
        a(0) = "New Value"                      '加上这一句的话，下面所有msgbox都应该显示 NewValue

        MsgBox(paraRecord.Index(0))
        MsgBox(paraRecord.paraIndex(0))
        MsgBox(paraRecord.paraName(0))

Sub test()

        Dim a(100) As String
        Dim b(100) As String
        Dim c(100) As String
        paraRecord.paraIndex = a
        paraRecord.Index = b
        paraRecord.paraName = c

        paraRecord.Index(0) = "0"               '相当于a(0)="0"
        paraRecord.paraIndex(0) = "1"           '相当于b(0)="1"
        paraRecord.paraName(0) = "value"        '相当于c(0)="value"

        MsgBox(paraRecord.Index(0))
        MsgBox(paraRecord.paraIndex(0))
        MsgBox(paraRecord.paraName(0))
    End Sub