MenuCommand.cs

using System.Collections;
using System.Collections.Specialized;
using System.Runtime.InteropServices;
using System.Security.Permissions;

namespace System.ComponentModel.Design
{
    [ComVisible(true)]
    [HostProtection(SecurityAction.LinkDemand, SharedState = true)]
    [PermissionSet(SecurityAction.LinkDemand, Name = "FullTrust")]
    [PermissionSet(SecurityAction.InheritanceDemand, Name = "FullTrust")]
    public class MenuCommand
    {
        private EventHandler execHandler;

        private EventHandler statusHandler;

        private CommandID commandID;

        private int status;

        private IDictionary properties;

        private const int ENABLED = 2;

        private const int INVISIBLE = 16;

        private const int CHECKED = 4;

        private const int SUPPORTED = 1;

        public virtual bool Checked
        {
            get
            {
                return (status & 4) != 0;
            }
            set
            {
                SetStatus(4, value);
            }
        }

        public virtual bool Enabled
        {
            get
            {
                return (status & 2) != 0;
            }
            set
            {
                SetStatus(2, value);
            }
        }

        public virtual IDictionary Properties
        {
            get
            {
                if (properties == null)
                {
                    properties = new HybridDictionary();
                }
                return properties;
            }
        }

        public virtual bool Supported
        {
            get
            {
                return (status & 1) != 0;
            }
            set
            {
                SetStatus(1, value);
            }
        }

        public virtual bool Visible
        {
            get
            {
                return (status & 0x10) == 0;
            }
            set
            {
                SetStatus(16, !value);
            }
        }

        public virtual CommandID CommandID => commandID;

        public virtual int OleStatus => status;

        public event EventHandler CommandChanged
        {
            add
            {
                statusHandler = (EventHandler)Delegate.Combine(statusHandler, value);
            }
            remove
            {
                statusHandler = (EventHandler)Delegate.Remove(statusHandler, value);
            }
        }

        public MenuCommand(EventHandler handler, CommandID command)
        {
            execHandler = handler;
            commandID = command;
            status = 3;
        }

        private void SetStatus(int mask, bool value)
        {
            int num = status;
            num = ((!value) ? (num & ~mask) : (num | mask));
            if (num != status)
            {
                status = num;
                OnCommandChanged(EventArgs.Empty);
            }
        }

        public virtual void Invoke()
        {
            if (execHandler != null)
            {
                try
                {
                    execHandler(this, EventArgs.Empty);
                }
                catch (CheckoutException ex)
                {
                    if (ex != CheckoutException.Canceled)
                    {
                        throw;
                    }
                }
            }
        }

        public virtual void Invoke(object arg)
        {
            Invoke();
        }

        protected virtual void OnCommandChanged(EventArgs e)
        {
            if (statusHandler != null)
            {
                statusHandler(this, e);
            }
        }

        public override string ToString()
        {
            string text = CommandID.ToString() + " : ";
            if ((status & 1) != 0)
            {
                text += "Supported";
            }
            if ((status & 2) != 0)
            {
                text += "|Enabled";
            }
            if ((status & 0x10) == 0)
            {
                text += "|Visible";
            }
            if ((status & 4) != 0)
            {
                text += "|Checked";
            }
            return text;
        }
    }
}