在VB中如何计算数字1~9的所有可能排列？

输出到TXT文件，求算法，谢谢

Private Sub Command1_Click()
Dim a(9) As Integer
n = CInt(InputBox("N="))
Open "d:\1234.txt" For Output As #1
k = 1
For i = 1 To n
a(i) = i
k = k * i
Next i
For i1 = 1 To k
For i = 1 To n
Print #1, a(i);
Next i
Print #1,
i = n - 1
Do While a(i) > a(i + 1)
i = i - 1
Loop
j = n
Do While a(j) < a(i)
j = j - 1
Loop
t = a(i): a(i) = a(j): a(j) = t
i = i + 1: j = n
Do While i < j
t = a(i): a(i) = a(j): a(j) = t
i = i + 1: j = j - 1
Loop
Next i1
Close #1
MsgBox "所有 " & k & " 个排列已经存入文件 d:\1234.txt，请查看！"
End Sub
以下是输入n=4时的内容：
1 2 3 4
1 2 4 3
1 3 2 4
1 3 4 2
1 4 2 3
1 4 3 2
2 1 3 4
2 1 4 3
2 3 1 4
2 3 4 1
2 4 1 3
2 4 3 1
3 1 2 4
3 1 4 2
3 2 1 4
3 2 4 1
3 4 1 2
3 4 2 1
4 1 2 3
4 1 3 2
4 2 1 3
4 2 3 1
4 3 1 2
4 3 2 1

最简单的算法就是从1一直循环到987654321，逐个数检查是否有重复。

如果位数是9位，且不能重复，那所有的可能：第一位有9种可能，第二位有9-1种，第三位有9-2种，以此类推，第9位位还剩一种可能。 9*8*7*6*5*4*3*2*1=362880 至于怎么写到vb里面，你再看看。我也写，写的好就回复，写不好，你只能自力更生了。

private sub command1_click() dim a as string for i = 1 to 35    for j = i + 1 to 36     for k = j + 1 to 37     for l = k + 1 to 38     for m = l + 1 to 39     for n = m + 1 to 40     if i + j + k + l + m + n >= 200 and i + j + k + l + m + n <= 250 then a = a & i & "," & j & "," & k & "," & l & "," & m & "," & n & vbcrlf next n, m, l, k, j, i text1.text = a end sub

排列的个数也不限吗？比如：1、135、123456789都是要得出的结果吗？