Shopping - A .NET shopping application for Pocket PC

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

namespace McSoft.UILib
{
	public delegate void DoubleClickEventHandler(object sender, EventArgs e);

	/// <summary>
	/// This is our base class for our List based Controls
	/// </summary>
	public abstract class OwnerDrawnListView : McSoftControl
	{		
		private int itemHeight         = -1;
		private int selectedIndex      = -1;
		private int previousClick = SystemInformation.DoubleClickTime + 1;

		VScrollBar vs;
		ArrayList items;

		public event EventHandler SelectedIndexChanged;
		public event DoubleClickEventHandler OnDoubleClick;

		public OwnerDrawnListView()
		{
			this.vs = new VScrollBar();
			this.vs.Parent      = this;
			this.vs.Visible     = false;
			this.vs.SmallChange = 1;
			this.vs.ValueChanged += new EventHandler(this.ScrollValueChanged);

			this.items = new ArrayList();
		}

		public ArrayList Items
		{
			get
			{
				return this.items;
			}
		}


		protected virtual void MouseDownEventCheck()
		{
		}


		protected VScrollBar VScrollBar
		{
			get
			{
				return this.vs;
			}
		}

		// Raise the SelectedIndexChanged event
		protected virtual void OnSelectedIndexChanged(EventArgs e)
		{
			if(this.SelectedIndexChanged != null)
				this.SelectedIndexChanged(this, e);
		}

		protected override void OnMouseDown(MouseEventArgs e)
		{
			this.SelectedIndex = this.vs.Value + (e.Y / this.ItemHeight);

			MouseDownEventCheck();

			// Invalidate the control so we can draw the item as selected.
			this.Refresh();
		}

		protected override void OnClick(EventArgs e)
		{
			int now = System.Environment.TickCount;
			if(now - previousClick <= SystemInformation.DoubleClickTime)			
				if(OnDoubleClick != null) OnDoubleClick(this.selectedIndex, e);
			previousClick = now;

			base.OnClick (e);
		}


		// Get or set index of selected item.
		public int SelectedIndex
		{
			get
			{
				return this.selectedIndex;
			}

			set
			{
				this.selectedIndex = value;

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

			}
		}

		protected void ScrollValueChanged(object o, EventArgs e)
		{
			this.Refresh();
		}

		protected virtual int ItemHeight
		{
			get
			{
				return this.itemHeight;
			}

			set
			{
				this.itemHeight = value;
			}
		}

		// If the requested index is before the first visible index then set the
		// first item to be the requested index. If it is after the last visible
		// index, then set the last visible index to be the requested index.
		public void EnsureVisible(int index)
		{
			if(index < this.vs.Value)
			{
				this.vs.Value = index;
				this.Refresh();
			}
			else if(index >= this.vs.Value + this.DrawCount)
			{
				this.vs.Value = index - this.DrawCount + 1;
				this.Refresh();
			}
		}		

		// Selected item moves when you use the keyboard up/down keys.
		protected override void OnKeyDown(KeyEventArgs e)
		{
			switch(e.KeyCode)
			{
				case Keys.Down:					
					if(this.SelectedIndex < this.vs.Maximum && this.selectedIndex < this.Items.Count - 1)
					{
						EnsureVisible(++this.SelectedIndex);
						this.Refresh();						
					}					
					break;
				case Keys.Up:
					if(this.SelectedIndex > this.vs.Minimum)
					{
						EnsureVisible(--this.SelectedIndex);
						this.Refresh();
					}
					break;
				case Keys.PageDown:
					this.SelectedIndex = Math.Min(this.vs.Maximum, this.SelectedIndex + this.DrawCount);
					EnsureVisible(this.SelectedIndex);
					this.Refresh();
					break;
				case Keys.PageUp:
					this.SelectedIndex = Math.Max(this.vs.Minimum, this.SelectedIndex - this.DrawCount);
					EnsureVisible(this.SelectedIndex);
					this.Refresh();
					break;
				case Keys.Home:
					this.SelectedIndex = 0;
					EnsureVisible(this.SelectedIndex);
					this.Refresh();
					break;
				case Keys.End:
					this.SelectedIndex = this.items.Count - 1;
					EnsureVisible(this.SelectedIndex);
					this.Refresh();
					break;
			}

			base.OnKeyDown(e);
		}

		// Calculate how many items we can draw given the height of the control.
		protected int DrawCount
		{
			get
			{
				if(this.vs.Value + this.vs.LargeChange > this.vs.Maximum)
					return this.vs.Maximum - this.vs.Value + 1;
				else
					return this.vs.LargeChange;
			}
		}
	}
}