C# tabControl1_DrawItem event firing constantly when I tried doublebuffering --cp.ExStyle |= 0x02000000

[liyanligt]

I have a form and it has tones of other controls(buttons,textbox, custom controls, labels, panel,gridview,,listview,). You can guess i had flickering issue. I tried doublebuffering,but it caused other question that tabControl1_DrawItem event firing constantly, how can it be fixed? Thank you very much.
I also want to note that without this code the problem does not happen, but the tabs flicker constantly and crazy without the "WS_EX_COMPOSITED hack" as Hans called it. With double buffering everything using this hack, it makes tabpages loaded well so it is staying in there necessarily。
Here related code:

         protected override CreateParams CreateParams
        {
            get
            {
                CreateParams cp = base.CreateParams;
                cp.ExStyle |= 0x02000000; //WS_EX_COMPOSITED
                this.Opacity = 1;
                return cp;
            }
        }

        private void tclTabControl_DrawItem(object sender, DrawItemEventArgs e)
        {
            if (e.Index == fTcl.SelectedIndex || (fTcl.TabCount - e.Index > 7))
            {
                if (!ResourcesManager.EtfSetting.IsWhiteStyle)
                {
                    //绘制主控件的背景
                    Rectangle rec3 = fTcl.ClientRectangle;
                    e.Graphics.FillRectangle(new SolidBrush(MyColor.BackColor), rec3);
                }
                SetStyle(ControlStyles.UserPaint, true);
                SetStyle(ControlStyles.AllPaintingInWmPaint, true); 
                SolidBrush orange = new SolidBrush(Color.Orange);
                SolidBrush pre = new SolidBrush(MyColor.RiskColor);
                SolidBrush dis = new SolidBrush(MyColor.DownColor);
                SolidBrush foreColor = new SolidBrush(MyColor.ForeColor);
                SolidBrush darkRed = new SolidBrush(Color.FromArgb(0, 128, 255));//Color.DarkRed
                SolidBrush selectedColor = new SolidBrush(MyColor.SelectedTabBackColor);
                SolidBrush unselectedColor = new SolidBrush(MyColor.UnselectedTabBackColor);
                StringFormat stringFormat = new StringFormat
                {
                    Alignment = StringAlignment.Center,
                    LineAlignment = StringAlignment.Center,
                };


                if (fTcl.TabPages.Count > 0)
                {
                    fTcl.BringToFront();
                    btnClose.BringToFront();
                    for (int i = 0; i < fTcl.TabPages.Count; i++)
                    {
                        TabPage page = fTcl.TabPages[i];
                        Rectangle rect = fTcl.GetTabRect(i);
                        SolidBrush backColor = unselectedColor;
                        foreach (Control ctrl in page.Controls)
                        {
                            if (ctrl is ETFOperateControl)
                            {
                                ETFOperateControl control = ctrl as ETFOperateControl;
                                if (control != null)
                                {
                                    TradeType trdType = control.TrdType;
                                    switch (trdType)
                                    {
                                        case TradeType.Dis:
                                            backColor = dis;
                                            break;
                                        case TradeType.Pre:
                                            backColor = pre;
                                            break;
                                        case TradeType.Mid:
                                            backColor = orange;
                                            break;
                                        default:
                                            break;
                                    }
                                    break;
                                }
                            }
                        }
                        float size = 9F;
                        Font font = new Font("微软雅黑", size);
                        SolidBrush fontColor = foreColor;
                        if (page == fTcl.SelectedTab)
                        {
                            font = new Font("微软雅黑", size, FontStyle.Bold);
                            fontColor = darkRed;
                            backColor = selectedColor;
                        }
                        e.Graphics.FillRectangle(backColor, rect);
                        e.Graphics.DrawString(page.Text, font, fontColor, rect, stringFormat);
                    }
                }
            }
       }

[RussKie]

Are you trying this in .NET Framework or .NET? Which version?