//简单读写方法
文件是否存在
System.IO.File.Exists(文件名)
'读文件
Dim sr As StreamReader = New StreamReader(文件名)
Dim line As String
' 行读取
Do
line = sr.ReadLine()
Loop Until line Is Nothing
'str = sr.ReadToEnd '全部读取
sr.Close()
'写文件
Dim sw As New System.IO.StreamWriter(文件名)
sw.Write(str)
sw.Close()