C#

public class FlowLayoutPanel : Panel
{
	public FlowLayoutPanel()
	{}
 
	private Orientation _orient = Orientation.Horizontal;
	[DefaultValue(Orientation.Horizontal)]
	public Orientation Orientation
	{
		get { return _orient; }
		set
		{
			_orient = value;
			RecalcLayout();
			Invalidate();
		}
	}
 
	private void RecalcLayout()
	{
		if (this.Controls.Count==0)
		{
			this.Size = new System.Drawing.Size(100,100);
			return;
		}

		int x=0,y=0,h=0,w=0;
		if (Orientation == Orientation.Horizontal)
		{
			// Width stays constant, height differs
			foreach (Control c in Controls)
			{
				if (x+c.Width > this.Width)
				{
					x = 0;
					y = h+1;
				}
				c.Left = x;
				c.Top = y;
				
				h = Math.Max(h,c.Bottom);
				x += c.Width;
			}
			this.Height = h;
		} 
		else
		{
			// Height stays constant, width differs
			foreach (Control c in Controls)
			{
				if (y+c.Height > this.Height)
				{
					y = 0;
					x = w+1;
				}
				c.Left = x;
				c.Top = y;
				
				w = Math.Max(w,c.Right);
				y += c.Height;
			}
			this.Width = w;
		}
	}
	
	protected override void OnResize(EventArgs eventargs)
	{
		RecalcLayout();
		base.OnResize (eventargs);
	}
	
	protected override void OnControlAdded(ControlEventArgs e)
	{
		RecalcLayout();
		base.OnControlAdded (e);
	}
	
	protected override void OnControlRemoved(ControlEventArgs e)
	{
		RecalcLayout();
		base.OnControlRemoved (e);
	}
}

//API function declaration
[DllImport("user32.Dll")]
public static extern IntPtr RemoveMenu(int hMenu, int nPosition,long wFlags); 

[DllImport("User32.Dll")]
public static extern IntPtr GetSystemMenu(int hWnd, bool bRevert);

[DllImport("User32.Dll")]
public static extern IntPtr GetMenuItemCount(int hMenu);

[DllImport("User32.Dll")]
public static extern IntPtr DrawMenuBar(int hwnd);
//

//constants declaration
private const int MF_BYPOSITION = 0x400;
private const int MF_REMOVE = 0x1000;
private const int MF_DISABLED = 0x2;
//

public void DisableCloseButton(int hWnd)
{
	IntPtr hMenu;
	IntPtr menuItemCount;

	//Obtain the handle to the form's system menu
	hMenu = GetSystemMenu(hWnd, false);

	// Get the count of the items in the system menu
	menuItemCount = GetMenuItemCount(hMenu.ToInt32());

	// Remove the close menuitem
	RemoveMenu(hMenu.ToInt32(), menuItemCount.ToInt32() - 1,MF_DISABLED | MF_BYPOSITION);

	// Remove the Separator 
	RemoveMenu(hMenu.ToInt32(), menuItemCount.ToInt32() - 2,MF_DISABLED | MF_BYPOSITION);

	// redraw the menu bar
	DrawMenuBar(hWnd);
}