如果滿足條件visual basic，我將如何更改數組元素的顏色

Question

Public Class Form1

    Dim r, r1, g, g1, b, b1 As Integer
    Dim grid(0 To 9, 0 To 9) As Label

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        timer1.Enabled = False
        Randomize()

        For row = 0 To 9
            For col = 0 To 9
                grid(row, col) = New Label

                grid(row, col).Width = 50
                grid(row, col).Height = 50
                grid(row, col).Left = 55 * col + 55
                grid(row, col).Top = 55 * row + 55
                grid(row, col).BackColor = Color.White

                Me.Controls.Add(grid(row, col))

                AddHandler grid(row, col).MouseEnter, AddressOf mouse_enter
            Next
        Next
    End Sub

    Private Sub mouse_enter(sender As Label, e As EventArgs)

        r = Int(Rnd() * 256)
        g = Int(Rnd() * 256)
        b = Int(Rnd() * 256)

        For row = 0 To 9
            For col = 0 To 9
                sender.BackColor = Color.FromArgb(r, g, b)
            Next
        Next
    End Sub

    Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
        Dim row As Integer
        Dim col As Integer

        For row = 0 To 9
            For col = 0 To 9
                r = Int(Rnd() * 256)
                g = Int(Rnd() * 256)
                b = Int(Rnd() * 256)

                grid(row, col).BackColor = Color.FromArgb(r, g, b)
            Next
        Next
    End Sub

    Private Sub Label2_Click(sender As Object, e As EventArgs) Handles Label2.Click
        Timer1.Enabled = True
        Timer1.Interval = 800
    End Sub
End Class

我想創建一個 10x10 的白框數組，一旦鼠標移過它們，它就會變成隨機的 rgb 顏色，效果很好。 但是，我還希望已經着色的框在每個 timer1 滴答聲中都變成一個新的 rgb 值。 使用上面的代碼，它只是在每次刻度時更改數組中的所有 100 個框，無論它是否被着色（用戶用鼠標瀏覽它）。有誰知道我將如何完成這項工作？

Answer 1

“我還希望已經着色的框在每個 timer1 滴答聲中都變成一個新的 rgb 值。” 由於每次計時器滴答時都會發生這種情況，因此If語句將屬於Timer1.Tick事件。 如果您希望鼠標輸入 label 后顏色保持不變，則以相同的方式將If添加到mouse_enter代碼中。

您可以檢查標簽的.BackColor是否仍然是White但是如果mouse_enter Sub中隨機選擇的.BackColor恰好是White怎么辦？ 你還想改變它嗎？ 可能最好使用 Label 的.Tag屬性。

調用mouse_enter時，將.Tag屬性設置為"Changed" 。 然后在.Tick事件中檢查 .Tag 屬性是否仍然是Nothing 。

雖然舊的 vb6 Rnd function 會工作，但最好使用 Z2D50972FECD376129545507F1062089Z Random ZA2F212ED4F8EBC42ABC1DDZ4C。 在表單級別創建此 class 的單個實例。

我將獲得隨機顏色的代碼移動到單獨的 function 中，因此我們不需要重復代碼。

Private grid(0 To 9, 0 To 9) As Label
Private Rand As New Random

Private Sub Form4_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    Timer1.Enabled = False
    For row = 0 To 9
        For col = 0 To 9
            grid(row, col) = New Label
            grid(row, col).Width = 50
            grid(row, col).Height = 50
            grid(row, col).Left = 55 * col + 55
            grid(row, col).Top = 55 * row + 55
            grid(row, col).BackColor = Color.White
            Controls.Add(grid(row, col))
            AddHandler grid(row, col).MouseEnter, AddressOf mouse_enter
        Next
    Next
End Sub

'The signature of this method must match the signature of Label.MouseEnter
'So sender must be As Object, not As Label
Private Sub mouse_enter(sender As Object, e As EventArgs)
    'Not all Objects have a .BackColor property so we must Cast to the underlying type, Label
    Dim l = DirectCast(sender, Label)
    l.BackColor = GetNewColor()
    l.Tag = "Changed"
End Sub

Private Function GetNewColor() As Color
    Dim r = Rand.Next(256)
    Dim g = Rand.Next(256)
    Dim b = Rand.Next(256)
    Dim NewColor = Color.FromArgb(r, g, b)
    Return NewColor
End Function

Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
    For row = 0 To 9
        For col = 0 To 9
            If grid(row, col).Tag Is Nothing Then '.Tag has never been set
                grid(row, col).BackColor = GetNewColor()
            End If
        Next
    Next
End Sub

Private Sub Label2_Click(sender As Object, e As EventArgs) Handles Label2.Click
    Timer1.Enabled = True
    Timer1.Interval = 800
End Sub