大家好！请问这样的数字排序如何做？

Dim a As Integer
Dim b As Integer
Dim c As Integer
Dim d As Integer
Dim e As Integer
a = Text0.Value

If a < 10 Then
Text2.Value = a
End If

If a > 10 And a < 100 Then
b = Left(a, 1)
c = Mid(a, 2, 1)
If b >= c Then
Text2.Value = c & b
Else
Text2.Value = b & c
End If
End If
If a > 100 And a < 1000 Then
b = Left(a, 1)
c = Mid(a, 2, 1)
d = Mid(a, 3, 1)
If b >= c And b >= d And c >= d Then
Text2.Value = d & c & b
Else
If c >= d And c >= b And b >= d Then
Text2.Value = d & b & c
Else
Text2.Value = b & c & d
End If
End If
End If