Visual Basic中如何自定义TabControl的颜色与边框？

以下是实现自定义背景色、表头颜色/文字色、移除边框的完整可运行代码，解决你之前代码中Tab丢失、样式混乱的问题：

Imports System.Drawing
Imports System.Windows.Forms

Public Class Form1
    Sub New()
        InitializeComponent()
        ' 绑定绘制事件
        AddHandler TabControl1.DrawItem, AddressOf TabControl1_DrawItem
        AddHandler TabControl1.MouseClick, AddressOf TabControl1_MouseClick

        ' 设置所有TabPage的背景色
        For Each tp As TabPage In TabControl1.TabPages
            tp.BackColor = Color.LightBlue ' 自定义TabPage背景色
        Next
    End Sub

    ' 自定义绘制Tab表头
    Private Sub TabControl1_DrawItem(sender As Object, e As DrawItemEventArgs)
        Dim tabControl As TabControl = DirectCast(sender, TabControl)
        Dim tabPage As TabPage = tabControl.TabPages(e.Index)
        Dim g As Graphics = e.Graphics
        Dim tabBounds As Rectangle = tabControl.GetTabRect(e.Index)

        ' 1. 绘制Tab背景（区分选中/未选中状态）
        Dim tabBackColor As Color
        Dim textColor As Color
        If e.Index = tabControl.SelectedIndex Then
            tabBackColor = Color.DarkSlateBlue ' 选中的Tab背景色
            textColor = Color.White ' 选中的Tab文字色
        Else
            tabBackColor = Color.LightSlateGray ' 未选中的Tab背景色
            textColor = Color.Black ' 未选中的Tab文字色
        End If

        ' 填充Tab背景（覆盖默认边框）
        g.FillRectangle(New SolidBrush(tabBackColor), tabBounds)

        ' 2. 绘制Tab文字
        Dim textFont As Font = tabPage.Font
        Dim textFormat As New StringFormat()
        textFormat.Alignment = StringAlignment.Center
        textFormat.LineAlignment = StringAlignment.Center
        g.DrawString(tabPage.Text, textFont, New SolidBrush(textColor), tabBounds, textFormat)

        ' 3. 移除TabPage的边框：通过绘制覆盖默认边框
        If e.Index = tabControl.SelectedIndex Then
            Dim pageBounds As Rectangle = tabControl.ClientRectangle
            pageBounds.Inflate(-1, -1) ' 缩小区域覆盖边框
            g.DrawRectangle(New Pen(tabControl.Parent.BackColor), pageBounds)
        End If
    End Sub

    ' 处理Tab点击切换（确保选中状态正确触发重绘）
    Private Sub TabControl1_MouseClick(sender As Object, e As MouseEventArgs)
        Dim tabControl As TabControl = DirectCast(sender, TabControl)
        Dim hitTest As TabControlHitTestInfo = tabControl.HitTest(e.X, e.Y)
        If hitTest.Type = TabControlHitTestType.TabItem Then
            tabControl.SelectedIndex = hitTest.Item.Index
            tabControl.Invalidate() ' 强制重绘
        End If
    End Sub

    Private Sub InitializeComponent()
        Me.TabPage2 = New System.Windows.Forms.TabPage()
        Me.TabPage1 = New System.Windows.Forms.TabPage()
        Me.TabControl1 = New System.Windows.Forms.TabControl()
        Me.TabControl1.SuspendLayout()
        Me.SuspendLayout()

        ' TabPage2
        Me.TabPage2.Location = New System.Drawing.Point(4, 22)
        Me.TabPage2.Name = "TabPage2"
        Me.TabPage2.Padding = New System.Windows.Forms.Padding(3)
        Me.TabPage2.Size = New System.Drawing.Size(557, 328)
        Me.TabPage2.TabIndex = 1
        Me.TabPage2.Text = "TabPage2"
        Me.TabPage2.UseVisualStyleBackColor = True

        ' TabPage1
        Me.TabPage1.Location = New System.Drawing.Point(4, 22)
        Me.TabPage1.Name = "TabPage1"
        Me.TabPage1.Padding = New System.Windows.Forms.Padding(3)
        Me.TabPage1.Size = New System.Drawing.Size(557, 328)
        Me.TabPage1.TabIndex = 0
        Me.TabPage1.Text = "TabPage1"
        Me.TabPage1.UseVisualStyleBackColor = True

        ' TabControl1 - 关键设置：启用OwnerDraw模式
        Me.TabControl1.Controls.Add(Me.TabPage1)
        Me.TabControl1.Controls.Add(Me.TabPage2)
        Me.TabControl1.DrawMode = System.Windows.Forms.TabDrawMode.OwnerDrawFixed
        Me.TabControl1.Location = New System.Drawing.Point(12, 21)
        Me.TabControl1.Name = "TabControl1"
        Me.TabControl1.SelectedIndex = 0
        Me.TabControl1.Size = New System.Drawing.Size(565, 354)
        Me.TabControl1.TabIndex = 0
        ' 移除默认边框样式
        Me.TabControl1.Appearance = TabAppearance.FlatButtons
        Me.TabControl1.ItemSize = New Size(120, 25) ' 自定义Tab表头大小

        ' Form1
        Me.BackColor = System.Drawing.SystemColors.Control
        Me.ClientSize = New System.Drawing.Size(589, 387)
        Me.Controls.Add(Me.TabControl1)
        Me.Name = "Form1"
        Me.TabControl1.ResumeLayout(False)
        Me.ResumeLayout(False)
    End Sub

    Friend WithEvents TabPage2 As System.Windows.Forms.TabPage
    Friend WithEvents TabPage1 As System.Windows.Forms.TabPage
    Friend WithEvents TabControl1 As System.Windows.Forms.TabControl
End Class

关键实现说明 #

• 启用自定义绘制：必须将TabControl的DrawMode设为OwnerDrawFixed，这是自定义样式的前提。同时设置Appearance = FlatButtons简化边框处理。
• 区分Tab状态：在DrawItem事件中判断当前Tab是否选中，分别设置不同的背景色和文字色，解决表头颜色丢失的问题。
• 移除边框：
  • 表头边框：通过用背景色填充整个Tab区域，覆盖默认边框。
  • TabPage边框：在选中Tab时，用父容器的背景色绘制一个覆盖默认边框的矩形。
• 修复Tab不可见问题：之前的代码硬编码了TabPage1，现在通过e.Index动态获取当前要绘制的Tab，确保所有Tab都能正确显示。
• 文字绘制优化：使用StringFormat实现文字居中，避免文字偏移。

内容的提问来源于stack exchange，提问作者Wabi-Sabi