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Help about popup control

I have created a popup control (derived from Control) and host (attach) 1 listbox to this popup control (obvious I will set property Dock of listbox to Fill)

PopupControl _popup = new
 PopupControl();
ListBox listbox = new
 ListBox();
listbox.Dock = DockStyles.Fill;
_popup.Controls.Add(listbox);

I override CreateParams on PopupControl to style:

protected
 override
 CreateParams CreateParams
            {
                get

                {
                    const
 int
 CS_DROPSHADOW = 0x00020000;
                    const
 int
 CS_NOCLOSEBUTTON = 0x200;
                    const
 int
 CS_NOVERTICALSCROLLBAR = ~0x200000;

                    CreateParams cp = base
.CreateParams;
                    if
 (mParent != null
 && !DesignMode)
                    {
                        cp.Style = (int
)(((long
)cp.Style & 0xffff) | 0x90200000);

                        cp.Style &= CS_NOVERTICALSCROLLBAR;

                        cp.ClassStyle |= CS_DROPSHADOW;

                        cp.Parent = mParent.Handle;
                        Point pos = mParent.PointToScreen(Point.Empty);
                        cp.X = pos.X;
                        cp.Y = pos.Y + mParent.Height;
                        cp.Width = this
.DefaultSize.Width;
                        cp.Height = this
.DefaultSize.Height;
                    }
                    return
 cp;
                }
            }

But when popup is displayed, it appear a space at the bottom, please see my captured image:
http://img24.imageshack.us/img24/4107/94256039.png

I think I need to modify CreateParams a little but I don't know how to do.
Please help me to disable the unwanted space. Thanks.

Le Vo Quang Friday, September 18, 2009 5:08 AM

Hi,

The remained part is because listbox.IntegralHeight property. The default setting of IntegralHeight property is true. Listbox will automatically resize to make sure an item is not partially displayed. Setting listbox.IntergralHeight to false will be ok.

listbox.IntegralHeight = false;

ListBox.IntegralHeight Property

Gets or sets a value indicating whether the control should resize to avoid showing partial items.

http://msdn.microsoft.com/en-us/library/system.windows.forms.listbox.integralheight.aspx

Best regards,

Ling Wang

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