一段简单的Ascii码加密程序错误

[earphone]

这是一段简单的Ascii码加密程序每次执行到6行和7行就报实时错识'5'：无效
的过程或参数，我总是不明白是哪错了，请教各位高手，谢谢

Private Sub MnuItemEcrypeSave_Click()
Dim Ecrype, Letter As String
Dim CharsInFile, I As Long
CharsInFile = Len(TxtNote.Text)
For I = I To CharsInFile
Letter = Mid(TxtNote.Text, I, 1)
Ecrype = Ecrype & Chr(Asc(Letter) + 1)
Next I
TxtNote.Text = Ecrype
End Sub

[hyzx2000]

这不是C语言.&有问题，要用And吧.位运算要用And,Or,Xor。

[mafangsan]

程序改成如下试试
Private Sub MnuItemEcrypeSave_Click()
Dim Ecrype, Letter As String
Dim CharsInFile, I As Long
CharsInFile = Len(TxtNote.Text)
For I = I To CharsInFile - 1
Letter = Mid(TxtNote.Text, I + 1, 1)
Ecrype = Ecrype & Chr(Asc(Letter) + 1)
Next I
TxtNote.Text = Ecrype
End Sub