A Floating Popup Control

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Runtime.InteropServices;
namespace Calculator
{
	/// <summary>
	/// Summary description for frmFloatingBase.
	/// </summary>
	public class frmFloatingBase : System.Windows.Forms.Form,IFloatingPopup
	{
		private System.ComponentModel.IContainer components;
		[DllImport("user32.dll")]
		public extern static int GetWindowRect(IntPtr hWnd,out Rect lpRect);

		public frmFloatingBase()
		{
			//
			// 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.components = new System.ComponentModel.Container();
			this.tmrForceActivate = new System.Windows.Forms.Timer(this.components);
			// 
			// tmrForceActivate
			// 
			this.tmrForceActivate.Tick += new System.EventHandler(this.tmrForceActivate_Tick);
			// 
			// frmFloatingBase
			// 
			this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
			this.ClientSize = new System.Drawing.Size(152, 144);
			this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;
			this.Name = "frmFloatingBase";
			this.ShowInTaskbar = false;
			this.StartPosition = System.Windows.Forms.FormStartPosition.Manual;
			this.Text = "frmFloatingBase";
			this.Leave += new System.EventHandler(this.CheckToHide);
			this.Deactivate += new System.EventHandler(this.CheckToHide);

		}
		#endregion

		private void CheckToHide(object sender, EventArgs e)
		{
			this.Hide();
		}

		private System.Windows.Forms.Timer tmrForceActivate;
		System.Windows.Forms.UserControl userControl;
		protected virtual void OnPopupHiding(CancelEventArgs e)
		{
			if(PopupHiding!=null)
				PopupHiding(this,e);
			if(e.Cancel==false)
			{
				base.Hide();
				OnPopupHidden(new EventArgs());
				if(this.Owner!=null)
					this.Owner.BringToFront();
			}
			else
			{
				this.tmrForceActivate.Enabled=true;
			}
			
		}
		protected virtual void OnPopupShowing(CancelEventArgs e)
		{
			if(PopupShowing!=null)
			{
				PopupShowing(this,e);
			}
			if(e.Cancel==false)
			{
				SetAutoLocation();
				base.Show();
				OnPopupShown(new EventArgs());
			}
		}
		protected virtual void OnPopupHidden(EventArgs e)
		{
			if(PopupHidden!=null)
				PopupHidden(this,e);
		}
		protected virtual void OnPopupShown(EventArgs e)
		{
			if(PopupShown!=null)
				PopupShown(this,e);
		}


		private void tmrForceActivate_Tick(object sender, System.EventArgs e)
		{
			this.tmrForceActivate.Enabled=false;
			this.Activate();
		}
		

		#region IFloatingPopup Members

		public event System.ComponentModel.CancelEventHandler PopupHiding;

		public event System.ComponentModel.CancelEventHandler PopupShowing;

		public event System.EventHandler PopupHidden;

		public event System.EventHandler PopupShown;

		public new void Show()
		{
			// TODO:  Add frmFloatingBase.Show implementation
			OnPopupShowing(new CancelEventArgs());
		}

		public new void Hide()
		{
			// TODO:  Add frmFloatingBase.Hide implementation
			OnPopupHiding(new CancelEventArgs());
		}

		public void ForceShow()
		{
			// TODO:  Add frmFloatingBase.ForceShow implementation
			this.tmrForceActivate.Enabled=true;
		}

		public UserControl UserControl
		{
			get
			{
				// TODO:  Add frmFloatingBase.UserControl getter implementation
				return userControl;
			}
			set
			{
				// TODO:  Add frmFloatingBase.UserControl setter implementation
				userControl=value;
			}
		}

		public void SetAutoLocation()
		{
			// TODO:  Add frmFloatingBase.SetAutoLocation implementation
			Rect rect;
			GetWindowRect(UserControl.Handle,out rect);
			Point tergatePoint;
			tergatePoint = new Point(rect.left ,rect.top + UserControl.Height );
			if(rect.left + UserControl.Width - this.Width < 0)
			{
				tergatePoint.X=0;
			}
			else
			{
				tergatePoint.X=rect.left - this.Width + UserControl.Width;
			}
			if(tergatePoint.X+this.Width>System.Windows.Forms.SystemInformation.WorkingArea.Right)
			{
				tergatePoint.X=System.Windows.Forms.SystemInformation.WorkingArea.Right-this.Width;
			}
			else if(tergatePoint.X<0)
				tergatePoint.X=0;
			if(tergatePoint.Y+this.Height>System.Windows.Forms.SystemInformation.WorkingArea.Bottom)
			{
				tergatePoint.Y=rect.top - this.Height;
			}
			if (tergatePoint.Y<0)
			{
				tergatePoint.Y=0;
			}
			if (tergatePoint.X<0)
			{
				tergatePoint.X=0;
			}
			this.Location=tergatePoint;

		}
		public Form GetPopupForm()
		{
			return this;
		}
		#endregion

	}
	public struct Rect
	{
		internal int left, top, right, bottom;
	}
	
}