xenadmin/XenAdmin/Controls/DropDownButton.cs

/* Copyright (c) Citrix Systems, Inc. 
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 * Redistribution and use in source and binary forms, 
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 * *   Redistributions of source code must retain the above 
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 *     following disclaimer. 
 * *   Redistributions in binary form must reproduce the above 
 *     copyright notice, this list of conditions and the 
 *     following disclaimer in the documentation and/or other 
 *     materials provided with the distribution. 
 * 
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 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, 
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
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using System;
using System.ComponentModel;
using System.Windows.Forms;
using System.Drawing;


namespace XenAdmin.Controls
{
    public partial class DropDownButton : Button
    {
        private ContextMenuStrip _contextMenuStrip;
        private bool _ignoreNextClick;

        public DropDownButton()
        {
            InitializeComponent();

            base.Image = Images.StaticImages.expanded_triangle;
            base.ImageAlign = ContentAlignment.MiddleRight;
            DoubleBuffered = true;
        }

        protected override void OnContextMenuStripChanged(EventArgs e)
        {
            base.OnContextMenuStripChanged(e);

            if (_contextMenuStrip != null)
            {
                _contextMenuStrip.Closed -= _contextMenuStrip_Closed;
                _contextMenuStrip.Opening -= _contextMenuStrip_Opening;
            }

            _contextMenuStrip = ContextMenuStrip;

            if (_contextMenuStrip != null)
            {
                _contextMenuStrip.Closed += _contextMenuStrip_Closed;
                _contextMenuStrip.Opening += _contextMenuStrip_Opening;

                // need to add dummy so context menu strip opens even it there aren't any items.
                if (_contextMenuStrip.Items.Count == 0)
                {
                    _contextMenuStrip.Items.Add(new ToolStripMenuItem { Name = "dummy" });
                }
            }
        }

        private void _contextMenuStrip_Opening(object sender, CancelEventArgs e)
        {
            _contextMenuStrip.Items.RemoveByKey("dummy");
        }

        private void _contextMenuStrip_Closed(object sender, ToolStripDropDownClosedEventArgs e)
        {
            // ensure that if the user clicks on the button when the menu is open, then the menu is closed,
            // (not opened again.)

            _ignoreNextClick = ClientRectangle.Contains(PointToClient(Cursor.Position));
        }

        protected override void OnClick(EventArgs e)
        {
            base.OnClick(e);

            if (_contextMenuStrip != null && !_ignoreNextClick)
            {
                _contextMenuStrip.Show(this, new Point(0, Height), ToolStripDropDownDirection.Default);
            }

            _ignoreNextClick = false;
        }

        [Browsable(false), DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
        public new Image Image
        {
            get
            {
                return base.Image;
            }
        }

        [Browsable(false), DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
        public new ContentAlignment ImageAlign
        {
            get
            {
                return base.ImageAlign;
            }
        }
    }
}