C#

public struct CommandContainer
{
    public System.Delegate method;
    public object[] parameters;
}

using System;
using System.Threading;
using System.Windows.Forms;

namespace CommandQueue
{

	public delegate void CommandFunction();
	/// <summary>
	/// Summary description for CommandQueue.
	/// </summary>
	public class CommandQueue:System.Collections.Queue
	{

		private ManualResetEvent m_ManualResetEvent;

		public CommandQueue()
		{
			//m_ManualResetEvent = new ManualResetEvent(true);
		}
	
		public override void Clear()
		{
			lock(this.SyncRoot)
			{
				// TODO:  Add CommandQueue.Clear implementation
				base.Clear ();
			}
		}
	
		public override object Dequeue()
		{
			lock(this.SyncRoot)
			{
				// TODO:  Add CommandQueue.Dequeue implementation
				return base.Dequeue ();
			}
		}
	
		public override object Peek()
		{
			lock(this.SyncRoot)
			{
				// TODO:  Add CommandQueue.Peek implementation
				return base.Peek ();
			}
		}
	
		public override void Enqueue(object obj)
		{
			lock(this.SyncRoot)
			{
				if(obj is CommandContainer)
				{
					base.Enqueue (obj);
				} 
				else
				{
					//TODO: Provide error code here
				}
			}
		}

		public void Enqueue(CommandFunction target)
		{
			lock(this.SyncRoot)
			{
				CommandContainer t_CommandContainer;
				t_CommandContainer.method = target;
				t_CommandContainer.parameters = null;
				base.Enqueue (t_CommandContainer);
			}
		}

		public void Enqueue(System.Delegate method, object[] parameters)
		{
			lock(this.SyncRoot)
			{
				CommandContainer t_CommandContainer;
				t_CommandContainer.method = method;
				t_CommandContainer.parameters = parameters;
				base.Enqueue (t_CommandContainer);
			}
		}

		/// <summary>
		/// Executes all commands in the que
		/// </summary>
		public void Flush()
		{
				Thread t_FlushThread = new Thread(new ThreadStart(FlushThreadStart));
			t_FlushThread.Name = "Flush Thread";
				t_FlushThread.Start();
				t_FlushThread.Join();
		}

		private void FlushThreadStart()
		{
			lock(this.SyncRoot)
			{
				for(int i = 0; i < this.Count; i++)
				{
					//m_ManualResetEvent.WaitOne();
					//m_ManualResetEvent.Reset();
					Thread t_RunThread = new Thread(new ThreadStart(RunCommand));
					t_RunThread.Name = i.ToString() + " : " + ((CommandContainer)base.Peek()).method.Method.ToString();
					t_RunThread.Start();
					t_RunThread.Join(500);
				}
			}
		}

		private void RunCommand()
		{
			object t_Command = base.Dequeue();
			if(t_Command is CommandContainer)
			{
				CommandContainer t_CommandContainer = (CommandContainer)t_Command;
				t_CommandContainer.method.DynamicInvoke(t_CommandContainer.parameters);
			}
			//m_ManualResetEvent.Set();
		}
	}
}

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

namespace CommandQueue
{
	/// <summary>
	/// Summary description for Form1.
	/// </summary>
	public class Form1 : System.Windows.Forms.Form
	{
		CommandQueue CQ = new CommandQueue();
		private System.Windows.Forms.Button button1;
		/// <summary>
		/// Required designer variable.
		/// </summary>
		private System.ComponentModel.Container components = null;

		public Form1()
		{
			//
			// Required for Windows Form Designer support
			//
			InitializeComponent();

			//
			// TODO: Add any constructor code after InitializeComponent call
			//
		}

		/// <summary>
		/// Clean up any resources being used.
		/// </summary>
		protected override void Dispose( bool disposing )
		{
			if( disposing )
			{
				if (components != null) 
				{
					components.Dispose();
				}
			}
			base.Dispose( disposing );
		}

		#region Windows Form Designer generated code
		/// <summary>
		/// Required method for Designer support - do not modify
		/// the contents of this method with the code editor.
		/// </summary>
		private void InitializeComponent()
		{
			this.button1 = new System.Windows.Forms.Button();
			this.SuspendLayout();
			// 
			// button1
			// 
			this.button1.Location = new System.Drawing.Point(8, 8);
			this.button1.Name = "button1";
			this.button1.Size = new System.Drawing.Size(72, 40);
			this.button1.TabIndex = 0;
			this.button1.Text = "button1";
			this.button1.Click += new System.EventHandler(this.button1_Click);
			// 
			// Form1
			// 
			this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
			this.ClientSize = new System.Drawing.Size(292, 273);
			this.Controls.Add(this.button1);
			this.Name = "Form1";
			this.Text = "Form1";
			this.ResumeLayout(false);

		}
		#endregion

		/// <summary>
		/// The main entry point for the application.
		/// </summary>
		[MTAThread]
		static void Main() 
		{
			Application.Run(new Form1());
		}

		private void button1_Click(object sender, System.EventArgs e)
		{
			for(int i =0; i< 2; i++)
			{
				CQ.Enqueue(new CommandFunction(Fctn0));
				CQ.Enqueue(new CommandFunction(Fctn1));
				CQ.Enqueue(new CommandFunction(Fctn2));
				CQ.Enqueue(new CommandFunction(Fctn3));
			}
			CQ.Flush();
		}

		private void Fctn0()
		{
			Console.WriteLine("0");
		}

		private void Fctn1()
		{
			Console.WriteLine("1A");
			this.button1.Invoke(new CommandFunction(foo));
			Console.WriteLine("1B");
		}

		private void Fctn2()
		{
			Console.WriteLine("2");
		}

		private void Fctn3()
		{
			Console.WriteLine("3");
		}

		private void foo()
		{
			//Code where invoke is required
			//this.button1.Width+=5;
			Console.WriteLine("Foo invoked from Fctn1");
		}
	}
}

OUTPUT:
The thread '0 : Void Fctn0()' (0x5f0) has exited with code 0 (0x0).
0
1A
The thread '2 : Void Fctn2()' (0x878) has exited with code 0 (0x0).
2
3
The thread '3 : Void Fctn3()' (0x894) has exited with code 0 (0x0).
The thread 'Flush Thread' (0x8d4) has exited with code 0 (0x0).
The thread '1 : Void Fctn1()' (0x54c) has exited with code 0 (0x0).
Foo invoked from Fctn1
1B