vb.net – 创建透明控件的一般解决方案是什么？

SetStyle(ControlStyles.SupportsTransparentBackColor,True)
Me.BackColor = Color.Transparent

Protected Overrides ReadOnly Property CreateParams As System.Windows.Forms.CreateParams
    Get
        Dim result As System.Windows.Forms.CreateParams = MyBase.CreateParams
        result.ExStyle = result.ExStyle Or WindowsMessages.WS_EX_TRANSPARENT
        Return result
    End Get
End Property

InvokePaintBackground(Parent,e.Graphics)

我创建了所需的一般透明度控件,解决方案是控件及其父级中所有兄弟节点的详细分解,并依赖于InvokePaint()和InvokePaintBackground()方法在OnPaintBackground()方法上准备递归绘图例程.通过连续定义较小的剪辑并与较低的控件相交,此方法可最大限度地减少绘图开销.

>完整的控件包括一种检测和响应兄弟控件’Invalidate方法的方法,有效地绘制透明控件的堆栈,并有效地允许动画底层控件上的完整alpha通道叠加.
>控件可以与子控件和父控件的所有排列交错,同时提供视觉上准确的透明度.
>对照中未考虑命中测试.
>此控件不会过度绘制在绘制事件期间未执行绘制的控件.这是一个很大的限制.
>要使用控件,只需从基础继承并重写OnPaint方法即可执行自定义绘图.只要首先调用对base方法的调用,也可以覆盖OnPaintBackground方法.

最后,如果有人想要包含无效处理的完整代码,请告诉我.如果您有系统绘制组件的解决方案,请告诉我.此外,如果你有一个更微不足道的解决方案,这意味着我浪费了大量的时间,我也不会对收到它感到沮丧！

提供了对OnPaintBackground方法的控件的摘录：

''' <summary>
''' Recursively paint all underlying controls in their relevant regions,stacking drawing operations as necessary.
''' </summary>
''' <param name="pevent"></param>
''' <remarks></remarks>
Protected Overrides Sub OnPaintBackground(pevent As System.Windows.Forms.PaintEventArgs)
    'Store clip and transform for reversion
    Dim initialClip As Region = pevent.Graphics.Clip
    Dim initialTransform As Drawing2D.Matrix = pevent.Graphics.Transform

    'Develop list of underlying controls
    Dim submarinedControls As New List(Of Control)
    For Each Control As Control In m_Siblings
        If Control.Visible AndAlso Above(Control) AndAlso Me.ClientRectangle.IntersectsWith(Control.RelativeClientRectangle(Me)) Then submarinedControls.Add(Control)
    Next

    'Prepare clip for parent draw
    Dim parentClip As System.Drawing.Region = New System.Drawing.Region(initialClip.GetRegionData)
    For Each Control As Control In submarinedControls
        parentClip.Exclude(Control.RelativeClientRectangle(Me))
    Next
    pevent.Graphics.Clip = parentClip

    'Evaluate control relationship to parent,temporarily adjusting transformation for parent redraw. This translation must be relative since the incoming graphics may already have a meaningful transform applied.
    Dim translation As Point = Parent.RelationTo(Me)
    pevent.Graphics.Transform = New Drawing2D.Matrix(1,1,initialTransform.OffsetX + translation.X,initialTransform.OffsetY + translation.Y)

    'Fully draw parent background
    InvokePaintBackground(Parent,pevent)
    InvokePaint(Parent,pevent)

    'Reset transform for sibling drawing
    pevent.Graphics.Transform = initialTransform

    'Develop initial clip of submarined siblings
    Dim siblingClip As System.Drawing.Region = New System.Drawing.Region(initialClip.GetRegionData)
    siblingClip.Exclude(parentClip)

    For Each Control As Control In submarinedControls
        'Define relative position of submarined sibling to self
        translation = Control.RelationTo(Me)

        'Define and apply clip *before* transformation
        Dim intersectionClip As New Region(Control.RelativeClientRectangle(Me))
        intersectionClip.Intersect(siblingClip)
        pevent.Graphics.Clip = intersectionClip

        'Apply transformation
        pevent.Graphics.Transform = New Drawing2D.Matrix(1,initialTransform.OffsetY + translation.Y)

        'Raise sibling control's paint events
        InvokePaintBackground(Control,pevent)
        InvokePaint(Control,pevent)

        'Revert transformation and exclude region
        pevent.Graphics.Transform = initialTransform
        siblingClip.Exclude(intersectionClip)
    Next

    'Revert transform and clip to pre-drawing state
    pevent.Graphics.Transform = initialTransform
    pevent.Graphics.Clip = initialClip
End Sub