vb统计字母问题

设定一个command1,一个text1；并手动设定Text1.MultiLine = True，要把text设定的足够大；程序不对各控件的位置和大小进行调整。代码如下：
Dim Pp(26) As Integer, I As Integer, Tt As String
Private Sub Command1_Click()
Tt = Text1.Text
For I = 1 To 26
Pp(I) = 0
Next
Call Iv
Text1.Text = Text1.Text + vbCrLf
For I = 1 To 26
If Pp(I) <> 0 Then
Text1.Text = Text1.Text + Chr(96 + I) + Str(Pp(I)) + Space(3)
End If
Next
Print
End Sub

Private Sub Iv()
Dim St As String
For I = 1 To Len(Tt)
St = LCase(Mid(Tt, I, 1))
If St >= "a" And St <= "z" Then
Pp(Asc(St) - 96) = Pp(Asc(St) - 96) + 1
End If
Next

End Sub
Private Sub Form_Load()
Text1.Text = ""
Command1.Caption = "开始统计"
End Sub

Private Sub Form_click()
dim a