Command.cs source code in C# .NET

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                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / WinForms / Managed / System / WinForms / Command.cs / 1305376 / Command.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

/* 
 */ 
namespace System.Windows.Forms {
 
    using System.Diagnostics;
    using System.Diagnostics.CodeAnalysis;

    using System; 
    using System.ComponentModel;
    using System.Windows.Forms; 
    using System.Drawing; 

    using Microsoft.Win32; 

    /// 
    /// 
    internal class Command : WeakReference { 

        private static Command[] cmds; 
        private static int icmdTry; 
        private static object internalSyncObject = new object();
        private const int idMin = 0x00100; 
        private const int idLim = 0x10000;

        internal int id;
 
        public Command(ICommandExecutor target)
            : base(target, false) { 
            AssignID(this); 
        }
 
        public virtual int ID {
            get {
                return id;
            } 
        }
 
        [SuppressMessage("Microsoft.Reliability", "CA2001:AvoidCallingProblematicMethods")] 
        protected static void AssignID(Command cmd) {
            lock(internalSyncObject) { 
                int icmd;

                if (null == cmds) {
                    cmds = new Command[20]; 
                    icmd = 0;
                } 
                else { 
                    Debug.Assert(cmds.Length > 0, "why is cmds.Length zero?");
                    Debug.Assert(icmdTry >= 0, "why is icmdTry negative?"); 

                    int icmdLim = cmds.Length;

                    if (icmdTry >= icmdLim) 
                        icmdTry = 0;
 
                    // First look for an empty slot (starting at icmdTry). 
                    for (icmd = icmdTry; icmd < icmdLim; icmd++)
                        if (null == cmds[icmd]) goto FindSlotComplete; 
                    for (icmd = 0; icmd < icmdTry; icmd++)
                        if (null == cmds[icmd]) goto FindSlotComplete;

                    // All slots have Command objects in them. Look for a command 
                    // with a null referent.
                    for (icmd = 0; icmd < icmdLim; icmd++) 
                        if (null == cmds[icmd].Target) goto FindSlotComplete; 

                    // Grow the array. 
                    icmd = cmds.Length;
                    icmdLim = Math.Min(idLim - idMin, 2 * icmd);

                    if (icmdLim <= icmd) { 
                        // Already at maximal size. Do a garbage collect and look again.
                        GC.Collect(); 
                        for (icmd = 0; icmd < icmdLim; icmd++) { 
                            if (null == cmds[icmd] || null == cmds[icmd].Target)
                                goto FindSlotComplete; 
                        }
                        throw new ArgumentException(SR.GetString(SR.CommandIdNotAllocated));
                    }
                    else { 
                        Command[] newCmds = new Command[icmdLim];
                        Array.Copy(cmds, 0, newCmds, 0, icmd); 
                        cmds = newCmds; 
                    }
                } 

FindSlotComplete:

                cmd.id = icmd + idMin; 
                Debug.Assert(cmd.id >= idMin && cmd.id < idLim, "generated command id out of range");
 
                cmds[icmd] = cmd; 
                icmdTry = icmd + 1;
            } 
        }

        public static bool DispatchID(int id) {
            Command cmd = GetCommandFromID(id); 
            if (null == cmd)
                return false; 
            return cmd.Invoke(); 
        }
 
        protected static void Dispose(Command cmd) {
            lock (internalSyncObject)
            {
                if (cmd.id >= idMin) { 
                    cmd.Target = null;
                    if (cmds[cmd.id - idMin] == cmd) 
                        cmds[cmd.id - idMin] = null; 
                    cmd.id = 0;
                } 
            }
        }

        public virtual void Dispose() { 
            if (id >= idMin)
                Dispose(this); 
        } 

        public static Command GetCommandFromID(int id) { 
            lock (internalSyncObject)
            {
                if (null == cmds)
                    return null; 
                int i = id - idMin;
                if (i < 0 || i >= cmds.Length) 
                    return null; 
                return cmds[i];
            } 
        }

        public virtual bool Invoke() {
            object target = Target; 
            if (!(target is ICommandExecutor))
                return false; 
            ((ICommandExecutor)target).Execute(); 
            return true;
        } 
    }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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Command.cs source code in C# .NET

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