xenadmin/XenAdmin/Commands/SelectionBroadcaster.cs

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using System;
using System.Windows.Forms;

namespace XenAdmin.Commands
{
    /// <summary>
    /// A class used to broad-cast MainWindow's current selection to <see cref="CommandToolStripMenuItem"/>s
    /// and <see cref="CommandToolStripButton"/>s.
    /// </summary>
    internal abstract class SelectionBroadcaster : IDisposable
    {
        /// <summary>
        /// Raises the <see cref="SelectionChanged"/> event.
        /// </summary>
        /// <param name="e">The <see cref="System.EventArgs"/> instance containing the event data.</param>
        protected virtual void OnSelectionChanged(EventArgs e)
        {
            EventHandler handler = SelectionChanged;

            if (handler != null)
            {
                handler(null, e);
            }
        }

        /// <summary>
        /// Binds this object to any <see cref="CommandToolStripMenuItem"/>s and <see cref="CommandToolStripButton"/>s
        /// that are found in the specified <see cref="ToolStripItemCollection"/>.
        /// </summary>
        public void BindTo(ToolStripItemCollection toolStripItems, IMainWindow mainWindow)
        {
            Util.ThrowIfParameterNull(toolStripItems, "toolStripItems");
            foreach (ToolStripItem item in toolStripItems)
            {
                ICommandControl commandControl = item as ICommandControl;

                if (commandControl != null)
                    BindTo(commandControl, mainWindow);

                ToolStripDropDownItem dropDownItem = item as ToolStripDropDownItem;

                if (dropDownItem != null)
                {
                    BindTo(dropDownItem.DropDownItems, mainWindow);
                }
            }
        }

        /// <summary>
        /// Bind this object to a single control
        /// </summary>
        public void BindTo(ICommandControl control, IMainWindow mainWindow)
        {
            if (control.Command == null)
            {
                return;
            }

            ((ICommand)control.Command).SetMainWindow(mainWindow);
            control.SelectionBroadcaster = this;
        }

        protected virtual void Dispose(bool disposing)
        {
            if (disposing)
            {
                SelectionChanged = null;
            }
        }

        /// <summary>
        /// Gets the current selection which will be used by listening <see cref="CommandToolStripMenuItem"/>s and 
        /// <see cref="CommandToolStripButton"/>s.
        /// </summary>
        public abstract SelectedItemCollection Selection { get; }

        public abstract void RefreshSelection();

        /// <summary>
        /// Occurs when the selection changes.
        /// </summary>
        public event EventHandler SelectionChanged;

        public abstract void SaveAndClearSelection();
        public abstract void RestoreSavedSelection();

        #region IDisposable Members

        /// <summary>
        /// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
        /// </summary>
        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        #endregion
    }
}