题目内容：

vb 大小写转换函数 大写换小写.小写换大写、.

优质解答

Private Sub Command1_Click()
Dim X As String
Dim I As Long
Dim S As String
Dim CH As String
X = Text1.Text
For I = 1 To Len(X)
CH = Mid(X,I,1)
If CH >= "a " And CH = "A" And CH