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

namespace TX.Framework.WindowUI.Controls.Docking
{
	public delegate string GetPersistStringCallback();

	public class DockContentHandler : IDisposable, IDockDragSource
	{
		public DockContentHandler(Form form) : this(form, null)
		{
		}

		public DockContentHandler(Form form, GetPersistStringCallback getPersistStringCallback)
		{
			if (!(form is IDockContent))
				throw new ArgumentException(Strings.DockContent_Constructor_InvalidForm, "form");

			m_form = form;
			m_getPersistStringCallback = getPersistStringCallback;

			m_events = new EventHandlerList();
			Form.Disposed +=new EventHandler(Form_Disposed);
			Form.TextChanged += new EventHandler(Form_TextChanged);
		}

		public void Dispose()
		{
			Dispose(true);
			GC.SuppressFinalize(this);
		}

		protected virtual void Dispose(bool disposing)
		{
			if(disposing)
			{
				lock(this)
				{
					DockPanel = null;
					if (m_autoHideTab != null)
						m_autoHideTab.Dispose();
					if (m_tab != null)
						m_tab.Dispose();

					Form.Disposed -= new EventHandler(Form_Disposed);
					Form.TextChanged -= new EventHandler(Form_TextChanged);
					m_events.Dispose();
				}
			}
		}

		private Form m_form;
		public Form Form
		{
			get	{	return m_form;	}
		}

		public IDockContent Content
		{
			get	{	return Form as IDockContent;	}
		}

        private IDockContent m_previousActive = null;
        public IDockContent PreviousActive
        {
            get { return m_previousActive; }
            internal set { m_previousActive = value; }
        }

        private IDockContent m_nextActive = null;
        public IDockContent NextActive
        {
            get { return m_nextActive; }
            internal set { m_nextActive = value; }
        }

		private EventHandlerList m_events;
		private EventHandlerList Events
		{
			get	{	return m_events;	}
		}

		private bool m_allowEndUserDocking = true;
		public bool AllowEndUserDocking
		{
			get	{	return m_allowEndUserDocking;	}
			set	{	m_allowEndUserDocking = value;	}
		}

		private double m_autoHidePortion = 0.25;
		public double AutoHidePortion
		{
			get	{	return m_autoHidePortion;	}
			set
			{
				if (value <= 0)
					throw(new ArgumentOutOfRangeException(Strings.DockContentHandler_AutoHidePortion_OutOfRange));

				if (m_autoHidePortion == value)
					return;

				m_autoHidePortion = value;

				if (DockPanel == null)
					return;

				if (DockPanel.ActiveAutoHideContent == Content)
					DockPanel.PerformLayout();
			}
		}

		private bool m_closeButton = true;
		public bool CloseButton
		{
			get	{	return m_closeButton;	}
			set
			{
				if (m_closeButton == value)
					return;

				m_closeButton = value;
				if (Pane != null)
					if (Pane.ActiveContent.DockHandler == this)
						Pane.RefreshChanges();
			}
		}

        private bool m_closeButtonVisible = true;
        /// <summary>
        /// Determines whether the close button is visible on the content
        /// </summary>
        public bool CloseButtonVisible
        {
            get { return m_closeButtonVisible; }
            set { m_closeButtonVisible = value; }
        }
		
		private DockState DefaultDockState
		{
			get
			{
				if (ShowHint != DockState.Unknown && ShowHint != DockState.Hidden)
					return ShowHint;

				if ((DockAreas & DockAreas.Document) != 0)
					return DockState.Document;
				if ((DockAreas & DockAreas.DockRight) != 0)
					return DockState.DockRight;
				if ((DockAreas & DockAreas.DockLeft) != 0)
					return DockState.DockLeft;
				if ((DockAreas & DockAreas.DockBottom) != 0)
					return DockState.DockBottom;
				if ((DockAreas & DockAreas.DockTop) != 0)
					return DockState.DockTop;

				return DockState.Unknown;
			}
		}

		private DockState DefaultShowState
		{
			get
			{
				if (ShowHint != DockState.Unknown)
					return ShowHint;

				if ((DockAreas & DockAreas.Document) != 0)
					return DockState.Document;
				if ((DockAreas & DockAreas.DockRight) != 0)
					return DockState.DockRight;
				if ((DockAreas & DockAreas.DockLeft) != 0)
					return DockState.DockLeft;
				if ((DockAreas & DockAreas.DockBottom) != 0)
					return DockState.DockBottom;
				if ((DockAreas & DockAreas.DockTop) != 0)
					return DockState.DockTop;
				if ((DockAreas & DockAreas.Float) != 0)
					return DockState.Float;

				return DockState.Unknown;
			}
		}

		private DockAreas m_allowedAreas = DockAreas.DockLeft | DockAreas.DockRight | DockAreas.DockTop | DockAreas.DockBottom | DockAreas.Document | DockAreas.Float;
		public DockAreas DockAreas
		{
			get	{	return m_allowedAreas;	}
			set
			{
				if (m_allowedAreas == value)
					return;

				if (!DockHelper.IsDockStateValid(DockState, value))
					throw(new InvalidOperationException(Strings.DockContentHandler_DockAreas_InvalidValue));

				m_allowedAreas = value;

				if (!DockHelper.IsDockStateValid(ShowHint, m_allowedAreas))
					ShowHint = DockState.Unknown;
			}
		}

		private DockState m_dockState = DockState.Unknown;
		public DockState DockState
		{
			get	{	return m_dockState;	}
			set
			{
				if (m_dockState == value)
					return;

                DockPanel.SuspendLayout(true);

				if (value == DockState.Hidden)
					IsHidden = true;
				else
					SetDockState(false, value, Pane);

                DockPanel.ResumeLayout(true, true);
			}
		}

		private DockPanel m_dockPanel = null;
		public DockPanel DockPanel
		{
			get { return m_dockPanel; }
			set
			{
				if (m_dockPanel == value)
					return;

				Pane = null;

				if (m_dockPanel != null)
					m_dockPanel.RemoveContent(Content);

				if (m_tab != null)
				{
					m_tab.Dispose();
					m_tab = null;
				}

				if (m_autoHideTab != null)
				{
					m_autoHideTab.Dispose();
					m_autoHideTab = null;
				}

				m_dockPanel = value;

				if (m_dockPanel != null)
				{
					m_dockPanel.AddContent(Content);
					Form.TopLevel = false;
					Form.FormBorderStyle = FormBorderStyle.None;
					Form.ShowInTaskbar = false;
                    Form.WindowState = FormWindowState.Normal;
					NativeMethods.SetWindowPos(Form.Handle, IntPtr.Zero, 0, 0, 0, 0,
						Win32.FlagsSetWindowPos.SWP_NOACTIVATE |
						Win32.FlagsSetWindowPos.SWP_NOMOVE |
						Win32.FlagsSetWindowPos.SWP_NOSIZE |
						Win32.FlagsSetWindowPos.SWP_NOZORDER |
						Win32.FlagsSetWindowPos.SWP_NOOWNERZORDER |
						Win32.FlagsSetWindowPos.SWP_FRAMECHANGED);
				}
			}
		}

		public Icon Icon
		{
			get	{	return Form.Icon;	}
		}

		public DockPane Pane
		{
			get {	return IsFloat ? FloatPane : PanelPane; }
			set
			{
				if (Pane == value)
					return;

                DockPanel.SuspendLayout(true);

				DockPane oldPane = Pane;

				SuspendSetDockState();
				FloatPane = (value == null ? null : (value.IsFloat ? value : FloatPane));
				PanelPane = (value == null ? null : (value.IsFloat ? PanelPane : value));
				ResumeSetDockState(IsHidden, value != null ? value.DockState : DockState.Unknown, oldPane);

                DockPanel.ResumeLayout(true, true);
			}
		}

		private bool m_isHidden = true;
		public bool IsHidden
		{
			get	{	return m_isHidden;	}
			set
			{
				if (m_isHidden == value)
					return;

				SetDockState(value, VisibleState, Pane);
			}
		}

		private string m_tabText = null;
		public string TabText
		{
            get { return m_tabText == null || m_tabText == "" ? Form.Text : m_tabText; }
			set
			{
				if (m_tabText == value)
					return;

				m_tabText = value;
				if (Pane != null)
					Pane.RefreshChanges();
			}
		}

		private DockState m_visibleState = DockState.Unknown;
		public DockState VisibleState
		{
			get	{	return m_visibleState;	}
			set
			{
				if (m_visibleState == value)
					return;

				SetDockState(IsHidden, value, Pane);
			}
		}

		private bool m_isFloat = false;
		public bool IsFloat
		{
			get	{	return m_isFloat;	}
			set
			{
				if (m_isFloat == value)
					return;

                DockState visibleState = CheckDockState(value);

				if (visibleState == DockState.Unknown)
					throw new InvalidOperationException(Strings.DockContentHandler_IsFloat_InvalidValue);

				SetDockState(IsHidden, visibleState, Pane);
			}
		}

        [SuppressMessage("Microsoft.Naming", "CA1720:AvoidTypeNamesInParameters")]
        public DockState CheckDockState(bool isFloat)
        {
            DockState dockState;

            if (isFloat)
            {
                if (!IsDockStateValid(DockState.Float))
                    dockState = DockState.Unknown;
                else
                    dockState = DockState.Float;
            }
            else
            {
                dockState = (PanelPane != null) ? PanelPane.DockState : DefaultDockState;
                if (dockState != DockState.Unknown && !IsDockStateValid(dockState))
                    dockState = DockState.Unknown;
            }

            return dockState;
        }

		private DockPane m_panelPane = null;
		public DockPane PanelPane
		{
			get	{	return m_panelPane;	}
			set
			{
				if (m_panelPane == value)
					return;

				if (value != null)
				{
					if (value.IsFloat || value.DockPanel != DockPanel)
						throw new InvalidOperationException(Strings.DockContentHandler_DockPane_InvalidValue);
				}

				DockPane oldPane = Pane;

                if (m_panelPane != null)
                    RemoveFromPane(m_panelPane);
				m_panelPane = value;
				if (m_panelPane != null)
				{
					m_panelPane.AddContent(Content);
					SetDockState(IsHidden, IsFloat ? DockState.Float : m_panelPane.DockState, oldPane);
				}
				else
					SetDockState(IsHidden, DockState.Unknown, oldPane);
			}
		}

        private void RemoveFromPane(DockPane pane)
        {
            pane.RemoveContent(Content);
            SetPane(null);
            if (pane.Contents.Count == 0)
                pane.Dispose();
        }

		private DockPane m_floatPane = null;
		public DockPane FloatPane
		{
			get	{	return m_floatPane;	}
			set
			{
				if (m_floatPane == value)
					return;

				if (value != null)
				{
					if (!value.IsFloat || value.DockPanel != DockPanel)
						throw new InvalidOperationException(Strings.DockContentHandler_FloatPane_InvalidValue);
				}

				DockPane oldPane = Pane;

                if (m_floatPane != null)
                    RemoveFromPane(m_floatPane);
				m_floatPane = value;
				if (m_floatPane != null)
				{
					m_floatPane.AddContent(Content);
					SetDockState(IsHidden, IsFloat ? DockState.Float : VisibleState, oldPane);
				}
				else
					SetDockState(IsHidden, DockState.Unknown, oldPane);
			}
		}

		private int m_countSetDockState = 0;
		private void SuspendSetDockState()
		{
			m_countSetDockState ++;
		}

		private void ResumeSetDockState()
		{
			m_countSetDockState --;
			if (m_countSetDockState < 0)
				m_countSetDockState = 0;
		}

		internal bool IsSuspendSetDockState
		{
			get	{	return m_countSetDockState != 0;	}
		}

		private void ResumeSetDockState(bool isHidden, DockState visibleState, DockPane oldPane)
		{
			ResumeSetDockState();
			SetDockState(isHidden, visibleState, oldPane);
		}

		internal void SetDockState(bool isHidden, DockState visibleState, DockPane oldPane)
		{
			if (IsSuspendSetDockState)
				return;

			if (DockPanel == null && visibleState != DockState.Unknown)
				throw new InvalidOperationException(Strings.DockContentHandler_SetDockState_NullPanel);

			if (visibleState == DockState.Hidden || (visibleState != DockState.Unknown && !IsDockStateValid(visibleState)))
				throw new InvalidOperationException(Strings.DockContentHandler_SetDockState_InvalidState);

            DockPanel dockPanel = DockPanel;
            if (dockPanel != null)
                dockPanel.SuspendLayout(true);

			SuspendSetDockState();

			DockState oldDockState = DockState;

			if (m_isHidden != isHidden || oldDockState == DockState.Unknown)
			{
				m_isHidden = isHidden;
			}
			m_visibleState = visibleState;
			m_dockState = isHidden ? DockState.Hidden : visibleState;

            if (visibleState == DockState.Unknown)
                Pane = null;
            else
            {
                m_isFloat = (m_visibleState == DockState.Float);

                if (Pane == null)
                    Pane = DockPanel.DockPaneFactory.CreateDockPane(Content, visibleState, true);
                else if (Pane.DockState != visibleState)
                {
                    if (Pane.Contents.Count == 1)
                        Pane.SetDockState(visibleState);
                    else
                        Pane = DockPanel.DockPaneFactory.CreateDockPane(Content, visibleState, true);
                }
            }

            if (Form.ContainsFocus)
                if (DockState == DockState.Hidden || DockState == DockState.Unknown)
                    DockPanel.ContentFocusManager.GiveUpFocus(Content);

            SetPaneAndVisible(Pane);

			if (oldPane != null && !oldPane.IsDisposed && oldDockState == oldPane.DockState)
				RefreshDockPane(oldPane);

			if (Pane != null && DockState == Pane.DockState)
			{
				if ((Pane != oldPane) ||
					(Pane == oldPane && oldDockState != oldPane.DockState))
					// Avoid early refresh of hidden AutoHide panes
					if ((Pane.DockWindow == null || Pane.DockWindow.Visible || Pane.IsHidden) && !Pane.IsAutoHide)
						RefreshDockPane(Pane);			
			}

            if (oldDockState != DockState)
            {
                if (DockState == DockState.Hidden || DockState == DockState.Unknown ||
                    DockHelper.IsDockStateAutoHide(DockState))
                    DockPanel.ContentFocusManager.RemoveFromList(Content);
                else
                    DockPanel.ContentFocusManager.AddToList(Content);

                OnDockStateChanged(EventArgs.Empty);
            }
			ResumeSetDockState();

            if (dockPanel != null)
                dockPanel.ResumeLayout(true, true);
		}

		private static void RefreshDockPane(DockPane pane)
		{
			pane.RefreshChanges();
			pane.ValidateActiveContent();
		}

		internal string PersistString
		{
			get	{	return GetPersistStringCallback == null ? Form.GetType().ToString() : GetPersistStringCallback();	}
		}

		private GetPersistStringCallback m_getPersistStringCallback = null;
		public GetPersistStringCallback GetPersistStringCallback
		{
			get	{	return m_getPersistStringCallback;	}
			set	{	m_getPersistStringCallback = value;	}
		}


		private bool m_hideOnClose = false;
		public bool HideOnClose
		{
			get	{	return m_hideOnClose;	}
			set	{	m_hideOnClose = value;	}
		}

		private DockState m_showHint = DockState.Unknown;
		public DockState ShowHint
		{
			get	{	return m_showHint;	}
			set
			{	
				if (!DockHelper.IsDockStateValid(value, DockAreas))
					throw (new InvalidOperationException(Strings.DockContentHandler_ShowHint_InvalidValue));

				if (m_showHint == value)
					return;

				m_showHint = value;
			}
		}

		private bool m_isActivated = false;
		public bool IsActivated
		{
			get	{	return m_isActivated;	}
		    internal set
		    {
	            if (m_isActivated == value)
		            return;

	            m_isActivated = value;
		    }
		}

		public bool IsDockStateValid(DockState dockState)
		{
			if (DockPanel != null && dockState == DockState.Document && DockPanel.DocumentStyle == DocumentStyle.SystemMdi)
				return false;
			else
				return DockHelper.IsDockStateValid(dockState, DockAreas);
		}

		private ContextMenu m_tabPageContextMenu = null;
		public ContextMenu TabPageContextMenu
		{
			get	{	return m_tabPageContextMenu;	}
			set	{	m_tabPageContextMenu = value;	}
		}

		private string m_toolTipText = null;
		public string ToolTipText
		{
			get	{	return m_toolTipText;	}
			set {	m_toolTipText = value;	}
		}

		public void Activate()
		{
			if (DockPanel == null)
				Form.Activate();
			else if (Pane == null)
				Show(DockPanel);
			else
			{
				IsHidden = false;
				Pane.ActiveContent = Content;
                if (DockState == DockState.Document && DockPanel.DocumentStyle == DocumentStyle.SystemMdi)
                {
                    Form.Activate();
                    return;
                }
                else if (DockHelper.IsDockStateAutoHide(DockState))
                    DockPanel.ActiveAutoHideContent = Content;

                if (!Form.ContainsFocus)
                    DockPanel.ContentFocusManager.Activate(Content);
			}
		}

        public void GiveUpFocus()
        {
            DockPanel.ContentFocusManager.GiveUpFocus(Content);
        }

		private IntPtr m_activeWindowHandle = IntPtr.Zero;
		internal IntPtr ActiveWindowHandle
		{
			get	{	return m_activeWindowHandle;	}
			set	{	m_activeWindowHandle = value;	}
		}

		public void Hide()
		{
			IsHidden = true;
		}

        internal void SetPaneAndVisible(DockPane pane)
        {
            SetPane(pane);
            SetVisible();
        }

		private void SetPane(DockPane pane)
		{
			if (pane != null && pane.DockState == DockState.Document && DockPanel.DocumentStyle == DocumentStyle.DockingMdi)
			{
				if (Form.Parent is DockPane)
					SetParent(null);
				if (Form.MdiParent != DockPanel.ParentForm)
				{
					FlagClipWindow = true;
					Form.MdiParent = DockPanel.ParentForm;
				}
			}
			else
			{
				FlagClipWindow = true;
				if (Form.MdiParent != null)
					Form.MdiParent = null;
				if (Form.TopLevel)
					Form.TopLevel = false;
				SetParent(pane);
			}
		}

		internal void SetVisible()
		{
			bool visible;

			if (IsHidden)
				visible = false;
			else if (Pane != null && Pane.DockState == DockState.Document && DockPanel.DocumentStyle == DocumentStyle.DockingMdi)
				visible = true;
			else if (Pane != null && Pane.ActiveContent == Content)
				visible = true;
			else if (Pane != null && Pane.ActiveContent != Content)
				visible = false;
			else
				visible = Form.Visible;

            if (Form.Visible != visible)
                Form.Visible = visible;
		}

		private void SetParent(Control value)
		{
			if (Form.Parent == value)
				return;

            //!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
            // Workaround of .Net Framework bug:
            // Change the parent of a control with focus may result in the first
            // MDI child form get activated. 
            //!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
            bool bRestoreFocus = false;
            if (Form.ContainsFocus)
            {
				//Suggested as a fix for a memory leak by bugreports
                if (value == null && !IsFloat)
                    DockPanel.ContentFocusManager.GiveUpFocus(this.Content);
                else
                {
                    DockPanel.SaveFocus();
                    bRestoreFocus = true;
                }
            }
            //!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

            Form.Parent = value;

            //!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
            // Workaround of .Net Framework bug:
            // Change the parent of a control with focus may result in the first
            // MDI child form get activated. 
            //!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
            if (bRestoreFocus)
                Activate();
            //!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
        }

		public void Show()
		{
			if (DockPanel == null)
				Form.Show();
			else
				Show(DockPanel);
		}

		public void Show(DockPanel dockPanel)
		{
			if (dockPanel == null)
				throw(new ArgumentNullException(Strings.DockContentHandler_Show_NullDockPanel));

			if (DockState == DockState.Unknown)
				Show(dockPanel, DefaultShowState);
			else			
				Activate();
		}

		public void Show(DockPanel dockPanel, DockState dockState)
		{
			if (dockPanel == null)
				throw(new ArgumentNullException(Strings.DockContentHandler_Show_NullDockPanel));

			if (dockState == DockState.Unknown || dockState == DockState.Hidden)
				throw(new ArgumentException(Strings.DockContentHandler_Show_InvalidDockState));

            dockPanel.SuspendLayout(true);

			DockPanel = dockPanel;

			if (dockState == DockState.Float && FloatPane == null)
				Pane = DockPanel.DockPaneFactory.CreateDockPane(Content, DockState.Float, true);
			else if (PanelPane == null)
			{
				DockPane paneExisting = null;
				foreach (DockPane pane in DockPanel.Panes)
					if (pane.DockState == dockState)
					{
						paneExisting = pane;
						break;
					}

				if (paneExisting == null)
					Pane = DockPanel.DockPaneFactory.CreateDockPane(Content, dockState, true);
				else
					Pane = paneExisting;
			}

			DockState = dockState;
            dockPanel.ResumeLayout(true, true); //we'll resume the layout before activating to ensure that the position
            Activate();                         //and size of the form are finally processed before the form is shown
		}

        [SuppressMessage("Microsoft.Naming", "CA1720:AvoidTypeNamesInParameters")]
		public void Show(DockPanel dockPanel, Rectangle floatWindowBounds)
		{
			if (dockPanel == null)
				throw(new ArgumentNullException(Strings.DockContentHandler_Show_NullDockPanel));

            dockPanel.SuspendLayout(true);

			DockPanel = dockPanel;
			if (FloatPane == null)
			{
				IsHidden = true;	// to reduce the screen flicker
				FloatPane = DockPanel.DockPaneFactory.CreateDockPane(Content, DockState.Float, false);
				FloatPane.FloatWindow.StartPosition = FormStartPosition.Manual;
			}

			FloatPane.FloatWindow.Bounds = floatWindowBounds;
			
			Show(dockPanel, DockState.Float);
			Activate();

            dockPanel.ResumeLayout(true, true);
		}

		public void Show(DockPane pane, IDockContent beforeContent)
		{
			if (pane == null)
				throw(new ArgumentNullException(Strings.DockContentHandler_Show_NullPane));

			if (beforeContent != null && pane.Contents.IndexOf(beforeContent) == -1)
				throw(new ArgumentException(Strings.DockContentHandler_Show_InvalidBeforeContent));

            pane.DockPanel.SuspendLayout(true);

			DockPanel = pane.DockPanel;
			Pane = pane;
			pane.SetContentIndex(Content, pane.Contents.IndexOf(beforeContent));
			Show();

            pane.DockPanel.ResumeLayout(true, true);
		}

		public void Show(DockPane previousPane, DockAlignment alignment, double proportion)
		{
			if (previousPane == null)
				throw(new ArgumentException(Strings.DockContentHandler_Show_InvalidPrevPane));

			if (DockHelper.IsDockStateAutoHide(previousPane.DockState))
				throw(new ArgumentException(Strings.DockContentHandler_Show_InvalidPrevPane));

            previousPane.DockPanel.SuspendLayout(true);

			DockPanel = previousPane.DockPanel;
			DockPanel.DockPaneFactory.CreateDockPane(Content, previousPane, alignment, proportion, true);
			Show();

            previousPane.DockPanel.ResumeLayout(true, true);
		}

		public void Close()
		{
			DockPanel dockPanel = DockPanel;
            if (dockPanel != null)
                dockPanel.SuspendLayout(true);
			Form.Close();
			if (dockPanel != null)
				dockPanel.ResumeLayout(true, true);

		}

		private DockPaneStripBase.Tab m_tab = null;
		internal DockPaneStripBase.Tab GetTab(DockPaneStripBase dockPaneStrip)
		{
            if (m_tab == null)
                m_tab = dockPaneStrip.CreateTab(Content);

            return m_tab;
		}

		private IDisposable m_autoHideTab = null;
		internal IDisposable AutoHideTab
		{
            get { return m_autoHideTab; }
            set { m_autoHideTab = value; }
		}

		#region Events
		private static readonly object DockStateChangedEvent = new object();
		public event EventHandler DockStateChanged
		{
			add	{	Events.AddHandler(DockStateChangedEvent, value);	}
			remove	{	Events.RemoveHandler(DockStateChangedEvent, value);	}
		}
		protected virtual void OnDockStateChanged(EventArgs e)
		{
			EventHandler handler = (EventHandler)Events[DockStateChangedEvent];
			if (handler != null)
				handler(this, e);
		}
		#endregion

		private void Form_Disposed(object sender, EventArgs e)
		{
			Dispose();
		}

		private void Form_TextChanged(object sender, EventArgs e)
		{
			if (DockHelper.IsDockStateAutoHide(DockState))
				DockPanel.RefreshAutoHideStrip();
			else if (Pane != null)
			{
				if (Pane.FloatWindow != null)
					Pane.FloatWindow.SetText();
				Pane.RefreshChanges();
			}
		}

		private bool m_flagClipWindow = false;
		internal bool FlagClipWindow
		{
			get	{	return m_flagClipWindow;	}
			set
			{
				if (m_flagClipWindow == value)
					return;

				m_flagClipWindow = value;
				if (m_flagClipWindow)
					Form.Region = new Region(Rectangle.Empty);
				else
					Form.Region = null;
			}
		}

        private ContextMenuStrip m_tabPageContextMenuStrip = null;
        public ContextMenuStrip TabPageContextMenuStrip
        {
            get { return m_tabPageContextMenuStrip; }
            set { m_tabPageContextMenuStrip = value; }
        }

        #region IDockDragSource Members

        Control IDragSource.DragControl
        {
            get { return Form; }
        }

        bool IDockDragSource.CanDockTo(DockPane pane)
        {
            if (!IsDockStateValid(pane.DockState))
                return false;

            if (Pane == pane && pane.DisplayingContents.Count == 1)
                return false;

            return true;
        }

        Rectangle IDockDragSource.BeginDrag(Point ptMouse)
        {
            Size size;
            DockPane floatPane = this.FloatPane;
            if (DockState == DockState.Float || floatPane == null || floatPane.FloatWindow.NestedPanes.Count != 1)
                size = DockPanel.DefaultFloatWindowSize;
            else
                size = floatPane.FloatWindow.Size;

            Point location;
			Rectangle rectPane = Pane.ClientRectangle;
            if (DockState == DockState.Document)
            {
                if (Pane.DockPanel.DocumentTabStripLocation == DocumentTabStripLocation.Bottom)
                    location = new Point(rectPane.Left, rectPane.Bottom - size.Height);
                else
                    location = new Point(rectPane.Left, rectPane.Top);
            }
            else
            {
                location = new Point(rectPane.Left, rectPane.Bottom);
                location.Y -= size.Height;
            }
            location = Pane.PointToScreen(location);

            if (ptMouse.X > location.X + size.Width)
                location.X += ptMouse.X - (location.X + size.Width) + Measures.SplitterSize;

            return new Rectangle(location, size);
        }

        public void FloatAt(Rectangle floatWindowBounds)
        {
            DockPane pane = DockPanel.DockPaneFactory.CreateDockPane(Content, floatWindowBounds, true);
        }

        public void DockTo(DockPane pane, DockStyle dockStyle, int contentIndex)
        {
			if (dockStyle == DockStyle.Fill)
			{
				bool samePane = (Pane == pane);
				if (!samePane)
					Pane = pane;

				if (contentIndex == -1 || !samePane)
					pane.SetContentIndex(Content, contentIndex);
				else
				{
					DockContentCollection contents = pane.Contents;
					int oldIndex = contents.IndexOf(Content);
					int newIndex = contentIndex;
					if (oldIndex < newIndex)
					{
						newIndex += 1;
						if (newIndex > contents.Count -1)
							newIndex = -1;
					}
					pane.SetContentIndex(Content, newIndex);
				}
			}
			else
			{
				DockPane paneFrom = DockPanel.DockPaneFactory.CreateDockPane(Content, pane.DockState, true);
				INestedPanesContainer container = pane.NestedPanesContainer;
				if (dockStyle == DockStyle.Left)
					paneFrom.DockTo(container, pane, DockAlignment.Left, 0.5);
				else if (dockStyle == DockStyle.Right) 
					paneFrom.DockTo(container, pane, DockAlignment.Right, 0.5);
				else if (dockStyle == DockStyle.Top)
					paneFrom.DockTo(container, pane, DockAlignment.Top, 0.5);
				else if (dockStyle == DockStyle.Bottom) 
					paneFrom.DockTo(container, pane, DockAlignment.Bottom, 0.5);

				paneFrom.DockState = pane.DockState;
			}
        }

        public void DockTo(DockPanel panel, DockStyle dockStyle)
        {
            if (panel != DockPanel)
                throw new ArgumentException(Strings.IDockDragSource_DockTo_InvalidPanel, "panel");

            DockPane pane;

            if (dockStyle == DockStyle.Top)
                pane = DockPanel.DockPaneFactory.CreateDockPane(Content, DockState.DockTop, true);
            else if (dockStyle == DockStyle.Bottom)
                pane = DockPanel.DockPaneFactory.CreateDockPane(Content, DockState.DockBottom, true);
            else if (dockStyle == DockStyle.Left)
                pane = DockPanel.DockPaneFactory.CreateDockPane(Content, DockState.DockLeft, true);
            else if (dockStyle == DockStyle.Right)
                pane = DockPanel.DockPaneFactory.CreateDockPane(Content, DockState.DockRight, true);
            else if (dockStyle == DockStyle.Fill)
                pane = DockPanel.DockPaneFactory.CreateDockPane(Content, DockState.Document, true);
            else
                return;
        }

        #endregion
    }
}
