TabControl.DrawItem 未在用户绘制的 TabControl 上触发

Question

嘿，我一直在尝试绘制自己的 TabControl 来摆脱 3D 阴影，但我没有取得太大成功。 DrawItem 事件目前没有触发。需要我自己拍吗？我该怎么做？

代码：

namespace NCPad
{
    public partial class NCE_TabControl : TabControl
    {
        Rectangle TabBoundary;
        RectangleF TabTextBoundary;

        public NCE_TabControl()
        {
            InitializeComponent();
            this.SetStyle(ControlStyles.UserPaint | ControlStyles.AllPaintingInWmPaint | ControlStyles.DoubleBuffer, true);
            this.DrawMode = TabDrawMode.OwnerDrawFixed;
            this.Paint += new PaintEventHandler(this.OnPaint);
            this.DrawItem += new DrawItemEventHandler(this.OnDrawItem);
        }

        protected void OnPaint(object sender, PaintEventArgs e)
        {
            Graphics g = e.Graphics;
            g.FillRectangle(new SolidBrush(Color.Red), e.ClipRectangle);
        }

        protected void OnDrawItem(object sender, DrawItemEventArgs e)
        {
            Graphics g = e.Graphics;
            g.FillRectangle(new SolidBrush(Color.Blue), this.TabBoundary);
            MessageBox.Show("hi");
        }

        protected override void OnLayout(LayoutEventArgs levent)
        {
            base.OnLayout(levent);

            this.TabBoundary = this.GetTabRect(0);
            this.TabTextBoundary = (RectangleF)this.GetTabRect(0);
        }
    }
}

Answer 1

我对此不确定，但我相信如果您将 ControlStyles.UserPaint 位指定为 true，则 DrawItem 将不会触发。不过，其他 ControlStyle（AllPaintingInWmPaint 和 DoubleBuffer）相互依赖，因此您也需要将它们删除。但是，不将 UserPaint 位设置为 true 将导致 Paint 事件不会被触发。我一直在做的是重写 OnPaintBackground 方法：

public partial class NCE_TabControl : TabControl
{
    Rectangle TabBoundary;
    RectangleF TabTextBoundary;
    StringFormat format = new StringFormat(); //for tab header text

    public NCE_TabControl()
    {   InitializeComponent();         
        this.SetStyle(ControlStyles.UserPaint | ControlStyles.AllPaintingInWmPaint | ControlStyles.DoubleBuffer, true);
        this.DrawMode = TabDrawMode.OwnerDrawFixed;
        this.format.Alignment = StringAlignment.Center;
        this.format.LineAlignment = StringAlignment.Center;
    }

    protected override void OnPaintBackground(PaintEventArgs pevent)
    {
        Graphics g = pevent.Graphics;
        g.FillRectangle(new SolidBrush(Color.Red), 0, 0, this.Size.Width, this.Size.Height);

        foreach (TabPage tp in this.TabPages)
        {
            //drawItem
            int index = this.TabPages.IndexOf(tp);

            this.TabBoundary = this.GetTabRect(index);
            this.TabTextBoundary = (RectangleF)this.GetTabRect(index);

            g.FillRectangle(new SolidBrush(Color.LightBlue), this.TabBoundary);
            g.DrawString("tabPage " + index.ToString(), this.Font, new SolidBrush(Color.Black), this.TabTextBoundary, format);
        }
    }
} 

我认为这对您有用，但也可能有其他方法可以做到这一点。

Answer 2

为了触发 DrawItem 事件，请在选项卡控件上设置 DrawMode = OwnerDrawFixed
http://msdn.microsoft.com/en -us/library/system.windows.forms.tabcontrol.drawitem.aspx

Answer 3

一种简单的方法是将 TabControl 的 Appearance 属性更改为 Buttons 或 FlatButtons 并将 DrawMode badk 设置为 <强>正常。