问一个弱弱的vb问题

randomize
a=array("123","321","12321")
text1.text=a(fix(rnd()*3)+1)

form上放 一个 多行，垂直滚动条的文本框，一个按钮。
程序：

Private Sub Command1_Click()
Dim a(2) As Integer
a(0) = 123
a(1) = 321
a(2) = 12321
Text1.Text = "原有数据：" + vbCrLf
Text1.Text = Text1.Text + CStr(a(0)) + vbCrLf
Text1.Text = Text1.Text + CStr(a(1)) + vbCrLf
Text1.Text = Text1.Text + CStr(a(2)) + vbCrLf
Text1.Text = Text1.Text + "随机挑选：" + vbCrLf
Randomize
Text1.Text = Text1.Text + CStr(a(Int(Rnd() * 3))) + vbCrLf
End Sub

我用的vb2008，代码是：
Public Class Form1
Dim a() As String = New String() {"123", "321", "12321"}

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Randomize()
TextBox1.Text = a(Fix(Rnd() * 3))