主题：请教：如何遍历字符串里的字符？

Dim str As String = "8888488"

Dim flag As Boolean = True
Dim ps As String = ""
For Each s As String In str
    If ps <> "" AndAlso ps <> s Then
        msgbox(s)
        flag = False
        Exit For
    End If
    ps = s
Next

msgbox(flag)