For-Next-Statement中的新隨機數重複相同的值

Question

我在for-next-statement中創建3個隨機字節。

但是，它們對於每個for-next都是相同的，例如「333」或「777」。

我想知道爲什麼這樣，我做錯了什麼。

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click 

    Dim s As String = String.Empty 

    For i As Integer = 0 To 2 
     s += GetRandomByte().ToString 
    Next 

    Me.TextBox1.Text = s 

End Sub 

Public Function GetRandomByte(Optional ByVal uLow As Byte = 1, Optional ByVal uHigh As Byte = 9) As Byte 

    Dim r As New Random 
    Dim b As Integer = r.Next(CInt(uLow), CInt(uHigh + 1)) 

    Return b 

End Function 

Answer 1

在你的構造新的隨機，給它一個新的種子每一次。我喜歡使用當前時間戳的哈希碼值

New Random(Now.GetHashCode) 

Answer 2

保持相同的情況下對所有呼叫：

Dim r As New Random() 

Public Function GetRandomByte(Optional ByVal uLow As Byte = 1, Optional ByVal uHigh As Byte = 9) As Byte 
    Return r.Next(CInt(uLow), CInt(uHigh + 1)) 
End Function 

，或者傳遞給隨機構造種子：

Dim r As New Random(CInt(Date.Now.Ticks And &h0000FFFF))