TabControl.DrawItem不会在用户绘制的TabControl上触发

Question

嘿,我一直在尝试绘制自己的TabControl以摆脱3D Shadow,但我没有取得多大成功.DrawItem事件此刻未触发.我必须亲自拍摄吗？我怎么做？

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

我不确定这一点,但我相信如果你将ControlStyles.UserPaint位指定为true,那么DrawItem将不会触发.但是,其他ControlStyles(AllPaintingInWmPaint和DoubleBuffer)彼此依赖,因此您也需要将它们关闭.但是,不将UserPaint位设置为true将导致不会触发Paint事件.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);
        }
    }
} 

我认为这对你有用,但也可能有其他方法.

Answer 2

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