在 .NET 2.0 中为 TabControl 应用视觉样式

• 下载源代码 - 14.8 Kb

引言

我曾经在使用 Visual Studio 2005 中包含的 TabControl 时遇到一个大问题。所以我为 TabControl 应用了一个“助记符”（快捷键）功能，因此我将 DrawMode 属性设置为 OwnerDrawFixed。但是，设置此属性会移除按钮的 XP 风格。

所以我尝试实现 DrawItem 事件来重新绘制按钮，但似乎没有效果。我甚至尝试了网上免费提供的“Sky Bound 组件”，但它不符合我的要求。

所以，最终我决定构建自己的控件。我在互联网上搜索了一些相关资源，但对找到的内容并不满意。

所以，这里是这个控件，我已经在其中应用了 XP 风格和快捷键功能。

背景

首先，我们需要设置双缓冲技术来改善绘制效果，并允许控件改变其外观

Me.SetStyle(ControlStyles.UserPaint, True)
Me.SetStyle(ControlStyles.AllPaintingInWmPaint, True)
Me.SetStyle(ControlStyles.DoubleBuffer, True)
Me.SetStyle(ControlStyles.ResizeRedraw, True)
Me.SetStyle(ControlStyles.SupportsTransparentBackColor, True)

然后，您需要重写 OnPaint 事件并绘制自己的控件。涉及的基本步骤是

Protected Overrides Function ProcessMnemonic(ByVal charCode As Char) As Boolean
    For Each p As TabPage In Me.TabPages
        If Control.IsMnemonic(charCode, p.Text) Then
            Me.SelectedTab = p
            Me.Focus()
            Return True
        End If
    Next p
    Return False
End Function 'ProcessMnemonic

          
Protected Overrides Sub OnPaint(ByVal e As _
          System.Windows.Forms.PaintEventArgs)
    MyBase.OnPaint(e)
    DrawControl(e.Graphics)
End Sub

Friend Sub DrawControl(ByVal g As Graphics)
    If Not Visible Then
        Return
    End If
    Dim render As New VisualStyleRenderer(VisualStyleElement.Tab.Pane.Normal)
    Dim TabControlArea As Rectangle = Me.ClientRectangle
    Dim TabArea As Rectangle = Me.DisplayRectangle
    TabArea.Y = TabArea.Y + 1
    TabArea.Width = TabArea.Width + 1
    Dim nDelta As Integer = SystemInformation.Border3DSize.Width
    TabArea.Inflate(nDelta, nDelta)
    render.DrawBackground(g, TabArea)
      
    Dim i As Integer = 0
    While i < Me.TabCount
        DrawTab(g, Me.TabPages(i), i)
        i += 1
    End While
      
End Sub
          
Friend Sub DrawTab(ByVal g As Graphics, ByVal tabPage _
           As TabPage, ByVal nIndex As Integer)
    Dim recBounds As Rectangle = Me.GetTabRect(nIndex)
      
    Dim tabTextArea As RectangleF = _
        CType(Me.GetTabRect(nIndex), RectangleF)
    Dim bSelected As Boolean = (Me.SelectedIndex = nIndex)
    Dim render As New VisualStyleRenderer(VisualStyleElement.Tab.Pane.Normal)
    render = New VisualStyleRenderer(VisualStyleElement.Tab.TabItem.Pressed)
    If bSelected Then
        recBounds.Height = recBounds.Height + 10
        render = New VisualStyleRenderer(VisualStyleElement.Tab.TabItem.Pressed)
        render.DrawBackground(g, recBounds)
        render.DrawEdge(g, recBounds, Edges.Diagonal, _
               EdgeStyle.Sunken, EdgeEffects.Flat)
    Else
        recBounds.Y = recBounds.Y + 1
        render = New VisualStyleRenderer(VisualStyleElement.Tab.TabItem.Normal)
        render.DrawBackground(g, recBounds)
        render.DrawEdge(g, recBounds, Edges.Diagonal, _
               EdgeStyle.Sunken, EdgeEffects.Flat)
    End If
    If (tabPage.ImageIndex >= 0) AndAlso _
                (Not (ImageList Is Nothing)) _
                AndAlso (Not (ImageList.Images(tabPage.ImageIndex) _
                Is Nothing)) Then
        Dim nLeftMargin As Integer = 8
        Dim nRightMargin As Integer = 2
        Dim img As Image = ImageList.Images(tabPage.ImageIndex)
        Dim rimage As Rectangle = New Rectangle(recBounds.X + _
                   nLeftMargin, recBounds.Y + 1, img.Width, img.Height)
        Dim nAdj As Single = CType((nLeftMargin + _
                    img.Width + nRightMargin), Single)
        rimage.Y += (recBounds.Height - img.Height) / 2
        tabTextArea.X += nAdj
        tabTextArea.Width -= nAdj
        g.DrawImage(img, rimage)
    End If
    Dim stringFormat As StringFormat = New StringFormat
    stringFormat.Alignment = StringAlignment.Center
    stringFormat.LineAlignment = StringAlignment.Center
    If FlagControl Then
        stringFormat.HotkeyPrefix = Drawing.Text.HotkeyPrefix.Show
    Else
        stringFormat.HotkeyPrefix = Drawing.Text.HotkeyPrefix.Hide
    End If
    Dim br As Brush
    br = New SolidBrush(tabPage.ForeColor)
    g.DrawString(tabPage.Text, Font, br, tabTextArea, stringFormat)
End Sub

Using the Code

要使用此代码，只需将引用添加到 TabControl 到新项目中，并将 TabControl 拖到您的窗体上即可。

注意

请留下您的评论、更正或补充，以表示感谢。您的反馈将不胜感激。