Question

想要在绘制的面板或其他控件上使用alphablend动画控件，但我的代码不能100％正常工作。我的代码现在正在闪烁动画。如果我将doublebuffered变量设置为true，我的控件后台将替换为黑色。如果我使用Me.Invalidate（）而不是Parent.Invalidate我的动画是非常错误的。

Imports System.Reflection

Public Class Form1
    Private Sub FlowLayoutPanel1_Paint(sender As Object, e As PaintEventArgs)
        Dim TheControl As Control = CType(sender, Control)
        Dim oRAngle As Rectangle = New Rectangle(0, 0, TheControl.Width, TheControl.Height)
        Dim oGradientBrush As Brush = New Drawing.Drawing2D.LinearGradientBrush(oRAngle, Color.White, Color.SteelBlue, Drawing.Drawing2D.LinearGradientMode.ForwardDiagonal)
        e.Graphics.FillRectangle(oGradientBrush, oRAngle)
    End Sub
    Public Shared Sub DoubleBufferedSet(ByVal dgv As Object, ByVal setting As Boolean)
        Dim dgvType As Type = dgv.[GetType]()
        Dim pi As PropertyInfo = dgvType.GetProperty("DoubleBuffered", BindingFlags.Instance Or BindingFlags.NonPublic)
        pi.SetValue(dgv, setting, Nothing)
    End Sub
    Private Sub FlowLayoutPanel1_Resize(sender As Object, e As EventArgs)
        sender.Invalidate()
    End Sub
    Dim flowlayoutpanel1 As New FlowLayoutPanels
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        flowlayoutpanel1.Dock = DockStyle.Fill
        AddHandler flowlayoutpanel1.Paint, AddressOf FlowLayoutPanel1_Paint
        AddHandler flowlayoutpanel1.Resize, AddressOf FlowLayoutPanel1_Resize
        Me.Controls.Add(flowlayoutpanel1)
        DoubleBufferedSet(flowlayoutpanel1, True)
        Dim testc1 As New OpaqControl
        testc1.Size = New Size(300, 100)
        flowlayoutpanel1.Controls.Add(testc1)
        Dim testc2 As New OpaqControl
        testc2.Size = New Size(300, 100)
        flowlayoutpanel1.Controls.Add(testc2)
    End Sub
End Class
Public Class OpaqControl
    Inherits Control
    Private Timer1 As New Timer()
    Dim up As Boolean = True
    Dim poss As Integer = 1
    Public Sub New()
        'DoubleBuffered = True
        AddHandler Timer1.Tick, AddressOf TickHandler
        Me.Timer1.Interval = 10
    End Sub
    Protected Sub TickHandler(sender As Object, e As EventArgs)
        If up Then
            poss += 2
            If poss >= 80 Then Me.Timer1.Enabled = False
        Else
            poss -= 2
            If poss <= 0 Then Me.Timer1.Enabled = False
        End If
        Parent.Invalidate(New Rectangle(Me.Location, Me.Size), True)
        'Me.Invalidate()
    End Sub
    Protected Overrides Sub OnMouseEnter(e As EventArgs)
        up = True
        Me.Timer1.Enabled = True
        MyBase.OnMouseEnter(e)
    End Sub
    Protected Overrides Sub OnMouseLeave(e As EventArgs)
        up = False
        Me.Timer1.Enabled = True
        MyBase.OnMouseLeave(e)
    End Sub
    Protected Overrides ReadOnly Property CreateParams() As CreateParams
        Get
            Dim cp As CreateParams = MyBase.CreateParams
            cp.ExStyle = cp.ExStyle Or &H20
            Return cp
        End Get
    End Property
    Protected Overrides Sub OnPaintBackground(pevent As PaintEventArgs)
    End Sub
    Protected Overrides Sub OnPaint(e As PaintEventArgs)
        e.Graphics.FillRectangle(New SolidBrush(Color.FromArgb(50, 0, 100, 255)), New Rectangle(0, 0, 300, 100))
        e.Graphics.FillRectangle(New SolidBrush(Color.FromArgb(50, 0, 0, 0)), New Rectangle(0, 100 - poss, 300, 80))
        e.Graphics.DrawString("Test", Font, Brushes.Yellow, New Point(100, 100 - poss))
    End Sub
End Class

抱歉我的英语不好。请尝试我的代码（尝试删除撇号）以了解我的问题。

我使用VB 2015。我不想使用任何第三方dll。我不想使用WPF。

Answer 1

它因为你可以看到父画本身而剧烈地闪烁。需要双缓冲来摆脱那个神器。不使用WS_EX_TRANSPARENT，这会破坏双缓冲。 Control类已经很好地支持透明度，利用这个功能：

Public Sub New()
    Me.DoubleBuffered = True
    Me.SetStyle(ControlStyles.SupportsTransparentBackColor, True)
    Me.BackColor = Color.Transparent
    AddHandler Timer1.Tick, AddressOf TickHandler
    Me.Timer1.Interval = 10
End Sub

删除CreateParams（）和OnPaintBackground（）覆盖。调用Me.Invalidate（）而不是Parent.Invalidate（）。而且它很柔滑。

VB.net在绘制的面板

1 个答案: