排序字符串的意外返回（）

  Private Sub bttSort_Click(sender As Object, e As EventArgs) Handles bttSort.Click
        DataView1.Rows.Clear()
        Dim i As Integer
        Dim j As Integer
        Dim temp As Integer
        For i = 0 To list1.Length - 1
            For j = (i + 1) To list1.Length - 1
                If list1(i) > list1(j) Then
                    temp = list1(i)
                    list1(i) = list1(j)
                    list1(j) = temp
                End If
            Next
        Next
        DataView1.Rows.Clear()
        For m As Integer = 0 To list1.Length - 1
            DataView1.Rows.Add(list1(m))
        Next
    End Sub
  Private Sub bttSort_Click(sender As Object, e