Writing a P2P Snippet sharing Extension for Visual Studio 2010 (VSX 2010)

using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Collections;
using System.Windows.Forms;
using System.ComponentModel;
using System.Drawing.Imaging;

namespace Sand.Services.CodeXchange.Client.Controls
{
	/// <summary>
	/// Panel control with a themeable header that can expand and collapse
	/// </summary>
	public class ExplorerGroup : Panel 
	{
		/// <summary>
		/// Event raised when the control expands or collapses
		/// </summary>
		public event EventHandler ExpandedChanged;

		private const int CHEVRON_X_PADDING = 22;
		private const int CHEVRON_Y_PADDING = 4;

		private bool m_Expanded = true;
		private bool m_MosueIsOverTitle = false;
		private int m_PanelHeight;

		private string m_Title = string.Empty;
		private Bitmap m_Icon = null;

		private System.ComponentModel.IContainer components;
		protected System.Windows.Forms.Label TitleLabel;


		public ExplorerGroup()
		{
			components = new System.ComponentModel.Container();

			InitializeComponent();
		}


		[Category("Appearance"), Description("The text contained in the control")]
		[Browsable(true)]
		public override string Text
		{
			get
			{
				return m_Title;
			}
			set
			{
				m_Title = value;
				Refresh();
			}
		}


		[Category("Appearance"), Description("Determines whether the panel's contents are shown or not")]
		[DefaultValue (true)]
		[Browsable(true)]
		public bool Expanded
		{
			get
			{
				return m_Expanded;
			}
			set
			{
				m_Expanded = value;
				OnExpandedChanged();
			}
		}

		[Category("Appearance"), Description("")]
		[Browsable(true)]
		public Bitmap Icon
		{
			get
			{
				return m_Icon;
			}
			set
			{
				m_Icon = value;
				Refresh();
			}
		}

		/// <summary>
		/// Updates the display to reflect the current expansion state
		/// </summary>
		private void ChangeExpansionDisplay()
		{
			if ( m_Expanded )
				Height = m_PanelHeight;
			else
			{
				m_PanelHeight = Height;
				Height = TitleLabel.Height;
			}
		}

		private Rectangle HeaderBounds
		{
			get
			{
				return new Rectangle( 0, 0, TitleLabel.Bounds.Width, TitleLabel.Bounds.Height );
			}
		}

		/// <summary>
		/// Called in order to raise the ExpandedChanged event
		/// </summary>
		protected void OnExpandedChanged()
		{		
			ChangeExpansionDisplay();

			if ( ExpandedChanged != null )
				ExpandedChanged( this, EventArgs.Empty );

			Refresh();
		}

		private void DrawChevrons(Graphics g, int x, int y, int offset)
		{
			// Determine the orientation of the pseudo-button
			if (!Expanded)
			{
				DrawChevron(g, x + offset + 1, y + 1*offset, -offset);
				DrawChevron(g, x + offset + 1, y + 2*offset, -offset);
			}
			else
			{
				DrawChevron(g, x + offset + 1, y + 2*offset, offset);
				DrawChevron(g, x + offset + 1, y + 3*offset, offset);
			}   
		}

		private void DrawChevron(Graphics g, int x, int y, int offset)
		{
			Pen p = new Pen(Color.White);
			Point[] points = { new Point(x, y),
								 new Point(x+Math.Abs(offset), y-offset),
								 new Point(x+2*Math.Abs(offset), y)
							 };
			g.DrawLines(p, points);
			p.Dispose();
		}

		/// <summary>
		/// Draws the header portion of the control
		/// </summary>
		/// <param name="graphics">Graphics object used for painting</param>
		protected void DrawHeader( Graphics graphics )
		{
			int x = TitleLabel.Bounds.Right - CHEVRON_X_PADDING;
			int y = TitleLabel.Bounds.Top + CHEVRON_Y_PADDING;

			Rectangle rect = new Rectangle( x, y, 12, 12 );
			Rectangle rect1 = new Rectangle(  x + ( rect.Width / 3 ) - 2, y + 3, 12, 12 );

			DrawChevrons ( graphics , 
				rect1.X , 
				rect1.Y , 
				rect1.Width / 4);

			DrawChevronEdge( graphics );
			DrawHeaderIcon ( graphics );
			DrawHeaderTitle ( graphics );

			if (m_MosueIsOverTitle)
			{
				TitleLabel.BackColor = System.Drawing.SystemColors.ActiveCaption;
			}
			else
			{
				TitleLabel.BackColor = System.Drawing.SystemColors.AppWorkspace;
			}
		}

		protected void DrawHeaderTitle( Graphics graphics )
		{
			using (Brush brush = new SolidBrush (System.Drawing.SystemColors.ActiveCaptionText))
			{
				Font font = new Font (Font.FontFamily , Font.Size , FontStyle.Bold);

				if (m_Icon != null)
				{
					graphics.DrawString (
						m_Title ,
						font ,
						brush , 
						20 , 
						4 , 
						StringFormat.GenericDefault);
				}
				else
				{
					graphics.DrawString (
						m_Title , 
						font , 
						brush , 
						4 , 
						4 , 
						StringFormat.GenericDefault);
				}
			}
		}

		protected void DrawHeaderIcon( Graphics graphics )
		{
			if (m_Icon != null)
				graphics.DrawImage (m_Icon , 4 , 4);
		}

		/// <summary>
		/// Draw a faint rectangle around the chevron if the mouse if currently over the title bar
		/// </summary>
		/// <param name="graphics">Graphics object used for painting</param>
		private void DrawChevronEdge( Graphics graphics )
		{
			if( m_MosueIsOverTitle )
			{
				Rectangle bounds = TitleLabel.Bounds;

				int x = bounds.Right - CHEVRON_X_PADDING;
				int y = bounds.Top + CHEVRON_Y_PADDING;

				Pen lightPen = new Pen( SystemColors.ControlLightLight );
				Pen darkPen = new Pen( Color.DarkGray );

				Rectangle rect = new Rectangle( x, y, 18 , 16);

				graphics.DrawLine( lightPen, x, y, x, y + rect.Height );
				graphics.DrawLine( lightPen, x, y, x + rect.Width, y );

				graphics.DrawLine( darkPen, x + rect.Width, y, x + rect.Width, y + rect.Height );
				graphics.DrawLine( darkPen, x + rect.Width, y + rect.Height, x, y + rect.Height );
			}		
		}

		#region Constituent Control Events
		private void TitleLabel_MouseUp(object sender, System.Windows.Forms.MouseEventArgs e)
		{
			if( e.Button == MouseButtons.Left && TitleLabel.Bounds.Contains( e.X, e.Y ) )
				Expanded = !Expanded;			
		}

		private void CollapsiblePanel_MouseLeave(object sender, System.EventArgs e)
		{
			TitleLabel.Cursor = Cursors.Default;
			m_MosueIsOverTitle = false;
			TitleLabel.Refresh();
		}

		private void TitleLabel_MouseLeave(object sender, System.EventArgs e)
		{
			TitleLabel.Cursor = Cursors.Default;
			m_MosueIsOverTitle = false;
			TitleLabel.Refresh();	
		}

		private void TitleLabel_MouseEnter(object sender, System.EventArgs e)
		{
			TitleLabel.Cursor = Cursors.Hand;
			m_MosueIsOverTitle = true;
			TitleLabel.Refresh();		
		}

		private void TitleLabel_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
		{
			//when the title is painted do the cutom rendering 
			DrawHeader( e.Graphics );
		}		
		#endregion

		#region Windows Form Designer generated code
		private void InitializeComponent()
		{
			this.TitleLabel = new System.Windows.Forms.Label();
			this.SuspendLayout();
			// 
			// TitleLabel
			// 
			this.TitleLabel.BackColor = System.Drawing.SystemColors.AppWorkspace;
			this.TitleLabel.Cursor = System.Windows.Forms.Cursors.Default;
			this.TitleLabel.Dock = System.Windows.Forms.DockStyle.Top;
			this.TitleLabel.Font = new System.Drawing.Font("Tahoma", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));
			this.TitleLabel.ForeColor = System.Drawing.SystemColors.HighlightText;
			this.TitleLabel.Location = new System.Drawing.Point(17, 17);
			this.TitleLabel.Name = "TitleLabel";
			this.TitleLabel.Size = new System.Drawing.Size(200, 24);
			this.TitleLabel.TabIndex = 0;
			this.TitleLabel.TextAlign = System.Drawing.ContentAlignment.MiddleLeft;
			this.TitleLabel.Paint += new System.Windows.Forms.PaintEventHandler(this.TitleLabel_Paint);
			this.TitleLabel.MouseEnter += new System.EventHandler(this.TitleLabel_MouseEnter);
			this.TitleLabel.MouseUp += new System.Windows.Forms.MouseEventHandler(this.TitleLabel_MouseUp);
			this.TitleLabel.MouseLeave += new System.EventHandler(this.TitleLabel_MouseLeave);
			// 
			// ExplorerGroup
			// 
			this.Controls.Add(this.TitleLabel);
			this.MouseLeave += new System.EventHandler(this.CollapsiblePanel_MouseLeave);
			this.ResumeLayout(false);

		}
		#endregion

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

	}
}