vb 中 提示错误 数组维数已定义是怎么回事?

Dim a(1 To 10) As Integer '已经定义数组含有10个元素，可改成Dim a() As Integer

Private Sub Command1_Click()
Picture1.Print "随机产生的10个100以内的元素是："
redim a(1 to 10) as integer '这里加一句
For i = 1 To 10
a(i) = Int(Rnd * 100)
Picture1.Print a(i);

Next i

Picture1.Print "------------"

End Sub

Private Sub Command2_Click()
Dim k%, j%, t%
For k = 1 To 10
For j = 1 To 10 - k
If a(j) < a(j + 1) Then
t = a(j): a(j) = a(j + 1): a(j + 1) = t
End If
Next j
Next k

Picture1.Print "10个元素按递减顺序排列："
For i = 1 To 10

Picture1.Print a(i);
Next i

End Sub

Private Sub Command3_Click()
Dim a(1 To 10) As Integer, k%, x%
x = Val(Text1)
For k = 1 To 10
If x < a(k) Then Exit For
Next k
ReDim Preserve a(n + 1) '这里不能再次定义数组的元素个数
For i = n To k Step -1
a(i + 1) = a(i)
Next i
a(k) = x
For i = 1 To n + 1
Picture1.Print a(i);
Next i

Dim a(1 To 10) As Integer, k%, x%
这个有问题吧，全局变量里面都已经定义了a（1 to 10），后面怎么又定义一遍啊