麻烦大佬看看哪一步出错了（个人觉得是在st那儿），导致最后不管测试都是一个结果，例如都显示是小写字母或者是数字。
Private Sub Command1_Click()
Dim s As String, st As String * 1, i As Integer, n As Integer
s = Text1.Text
i = Text2.Text
n = Len(s)
If i > n Then
MsgBox "指定位置出错，请重新输入！"
Text2 = ""
Else
st = Text1.Text
Select Case st
Case "A" To "Z"
Text3.Text = "是大写字母"
Case "a" To "z"
Text3.Text = "是小写字母"
Case "0" To "9"
Text3.Text = "是数字字符"
Case Else
Text3.Text = "是其他字符"
End Select
End If
End Sub

顶一下

顶一下

①i=val（text2）
②st=mid（text1，i，1）