6

快要在这里失去理智了。我已经在谷歌上搜索了一个小时，试图解决这个轻微但令人难以置信的严重问题。

我的TabControl表格上有两个标签。每个选项卡都有一个 16x16 的图标和一些文本。这里没有什么疯狂的事情。

在某些情况下，我需要让其中一个选项卡图标闪烁。所以我创建了两个图像，light_on.png并将light_off.png它们添加ImageList到TabControl. 我设置了一个背景计时器，它在两个图像之间切换以模拟闪烁的图标。工作正常。

但是，它会导致所有选项卡标题重新绘制，从而使它们闪烁。

TabControl无论您尝试做什么，都不支持双缓冲。

我发现人们使用以下代码成功地驯服了闪烁：

    Protected Overrides ReadOnly Property CreateParams() As CreateParams 
        Get
            Dim cp As CreateParams = MyBase.CreateParams
            cp.ExStyle = cp.ExStyle Or &H2000000
            Return cp
        End Get
    End Property

这很有效，因为它不会闪烁......但图标也不会在视觉上发生变化，除非鼠标光标悬停在导致重绘的东西上。

有没有人有任何可能有效的替代解决方案或技巧？这实际上是该软件的一个非常重要的功能。

骨架代码：

Public Class Form1
    Dim BlinkTimer As Windows.Forms.Timer
    Dim BlinkToggler As Boolean = False

    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        InitBlinker()
    End Sub

    Private Sub InitBlinker()
        BlinkTimer = New Windows.Forms.Timer
        AddHandler BlinkTimer.Tick, AddressOf Blinker_Tick
        With BlinkTimer
            .Enabled = True
            .Interval = 250
        End With
        StartBlinker()
    End Sub
    Public Sub StartBlinker()
        SomeTabPage.ImageKey = "light_off.png"
        BlinkToggler = False
        BlinkTimer.Start()
    End Sub
    Public Sub StopBlinker()
        SomeTabPage.ImageKey = "light_off.png"
        BlinkToggler = False
        BlinkTimer.Stop()
    End Sub
    Private Sub Blinker_Tick()
        If BlinkToggler Then
            SomeTabPage.ImageKey = "light_on.png"
        Else
            SomeTabPage.ImageKey = "light_off.png"
        End If
        BlinkToggler = Not BlinkToggler
    End Sub

End Class
4

1 回答 1

3

这是手动绘制图像的快速技巧（有几件事需要调整，但这是一个开始）。

Imports System.Threading

Public Class MyTabControl
    Inherits TabControl

    Private tabsImages As New Concurrent.ConcurrentDictionary(Of TabPage, List(Of String))
    Private tabsImagesKeys As New Concurrent.ConcurrentDictionary(Of TabPage, String)

    Private cycleImagesThread As Thread

    Private mInterval As Integer = 500

    Public Sub New()
        Me.SetStyle(ControlStyles.OptimizedDoubleBuffer, True)

        Me.DrawMode = TabDrawMode.OwnerDrawFixed

        cycleImagesThread = New Thread(AddressOf CycleImagesLoop)
        cycleImagesThread.Start()
    End Sub

    Protected Overrides Sub OnHandleCreated(e As EventArgs)
        If Me.FindForm IsNot Nothing Then AddHandler CType(Me.FindForm, Form).FormClosing, Sub() cycleImagesThread.Abort()
        MyBase.OnHandleCreated(e)
    End Sub

    Private Sub CycleImagesLoop()
        Do
            Thread.Sleep(mInterval)

            If tabsImagesKeys.Count > 0 Then
                For Each tabImageKey In tabsImagesKeys
                    Dim index = tabsImages(tabImageKey.Key).IndexOf(tabImageKey.Value)
                    index += 1
                    index = index Mod tabsImages(tabImageKey.Key).Count
                    tabsImagesKeys(tabImageKey.Key) = tabsImages(tabImageKey.Key)(index)
                Next

                Me.Invalidate()
            End If
        Loop
    End Sub

    Public Property Interval As Integer
        Get
            Return mInterval
        End Get
        Set(value As Integer)
            mInterval = value
        End Set
    End Property

    Public Sub SetImages(tabPage As TabPage, images As List(Of String))
        If tabsImages.ContainsKey(tabPage) Then
            tabsImages(tabPage) = images
        Else
            tabsImages.TryAdd(tabPage, images)
        End If
        tabsImagesKeys(tabPage) = images.First()
    End Sub

    Protected Overrides Sub OnDrawItem(e As DrawItemEventArgs)
        Dim g As Graphics = e.Graphics
        Dim r As Rectangle = e.Bounds
        Dim tab As TabPage = Me.TabPages(e.Index)
        Dim tabImage As Image

        Using b = New SolidBrush(IIf(e.State = DrawItemState.Selected, Color.White, Color.FromKnownColor(KnownColor.Control)))
            g.FillRectangle(b, r)
        End Using

        If tabsImagesKeys.Count > 0 OrElse Me.ImageList IsNot Nothing Then
            If tabsImagesKeys.ContainsKey(tab) Then
                tabImage = Me.ImageList.Images(tabsImagesKeys(tab))
                g.DrawImageUnscaled(tabImage, r.X + 4, r.Y + (r.Height - tabImage.Height) / 2)
            End If
            r.X += Me.ImageList.ImageSize.Width + 4
        End If

        Using b = New SolidBrush(tab.ForeColor)
            Dim textSize = g.MeasureString(tab.Text, tab.Font)
            g.DrawString(tab.Text, tab.Font, b, r.X, r.Y + (r.Height - textSize.Height) / 2)
        End Using

        MyBase.OnDrawItem(e)
    End Sub
End Class

请按照以下步骤设置控件：

  1. 首先，为 分配一个ImageList控件MyTabControl并用图像填充它。

  2. 接下来，调用SetImages方法来定义应在每个选项卡上显示哪些图像。

    MyTabControl1.SetImages(TabPage1, New List(Of String) From {"icon.gif", "icon2.gif"}) MyTabControl1.SetImages(TabPage2, New List(Of String) From {"myImage1.gif", "myImage2. gif"})

请注意，该SetImages方法的第二个参数是应该存在于ImageList. 控制将完成其余的工作......

于 2013-01-12T08:17:59.157 回答