Listview

using System.Drawing;
using System.Windows.Forms;
using System.Runtime.InteropServices;

//********************************************************************************
//*                  Created by Predrag Gruevski (obi1kenobi)                    *
//*                      Originally published on VBForums                        *
//*                                02.01.2010                                    *
//*            Feel free to use this code for any use you see fit,               *
//*       just please do not alter this info box and credit me for the code.     *
//********************************************************************************

public class TransparentListView : ListView
{

	#region " Consts "

	const int CLR_NONE = -1;
	const int LVM_FIRST = 0x1000;
	const int LVM_GETBKCOLOR = LVM_FIRST + 0;
	const int LVM_SETBKCOLOR = LVM_FIRST + 1;
	const int WM_HSCROLL = 0x114;
	const int WM_VSCROLL = 0x115;

	const int SBM_SETSCROLLINFO = 0xe9;
	[DllImport("user32", EntryPoint = "SendMessageA", CharSet = CharSet.Ansi, SetLastError = true, ExactSpelling = true)]
	private static extern int SendMessage(int hwnd, int wMsg, int wParam, int lParam);
	#endregion

	#region " APIs "


	#endregion

	#region " Variables "

	private Timer tmr = new Timer();
	private Stopwatch stp = new Stopwatch();
	private bool _redrawOnMouseMove;
	private int _interval = 300;
	private Color _highlightColor;
	private Color _errorColor;

	private int itemHeight;
	#endregion

	#region " Constructors "

	/// <summary>
	/// Creates a new TransparentListView object.
	/// </summary>
	/// <remarks></remarks>
	public TransparentListView()
	{
		this.OwnerDraw = true;
		this.DoubleBuffered = true;
		this.Font = new Font("Calibri", 11, FontStyle.Regular, GraphicsUnit.Point);
		tmr.Interval = _interval;
	}

	#endregion

	#region " Properties "

	/// <summary>
	/// The color to use when a certain ListViewItem has unresolved issues.
	/// </summary>
	public Color ErrorTextColor {
		get { return _errorColor; }
		set { _errorColor = value; }
	}

	/// <summary>
	/// The color to use when highlighting an item.
	/// </summary>
	public Color HighlightColor {
		get { return _highlightColor; }
		set { _highlightColor = value; }
	}

	/// <summary>
	/// The intervals at which to redraw the control when scrolling. Higher values are reccomended for less powerful CPUs.
	/// Decrease this value if experiencing choppy redraws during scrolling. Values below 5-6ms may result in extreme CPU use.
	/// </summary>
	public int RedrawInterval {
		get { return _interval; }
		set {
			if (value <= 0) {
				_interval = 15;
				//15ms should result in appx. 60 refreshes per second (60Hz) - only when required
				tmr.Interval = 15;
			} else {
				_interval = value;
				tmr.Interval = value;
			}
		}
	}

	/// <summary>
	/// True if the control should be redrawn when the mouse is moved, otherwise False.
	/// </summary>
	/// <remarks>There have been some issues with the Set method, so it's temporarily disabled and has no effect.</remarks>
	public bool RedrawOnMouseMove {
		get { return _redrawOnMouseMove; }
			//_redrawOnMouseMove = value
		set { }
	}

	#endregion

	#region " Methods "

	#region " Overriden Methods "

	protected override void OnMouseWheel(System.Windows.Forms.MouseEventArgs e)
	{
		base.OnMouseWheel(e);
		OnListViewScrolled(EventArgs.Empty);
	}

	protected override void OnMouseUp(System.Windows.Forms.MouseEventArgs e)
	{
		if (this.Items.Count > 0) {
			ListViewItem clickedItem = this.GetItemAt(5, e.Y);
			if ((clickedItem != null)) {
				clickedItem.Selected = true;
				clickedItem.Focused = true;
				//Else
				//Dim bnd As Integer = Me.Items.Count - 1
				//For i As Integer = 0 To bnd
				// clickedItem = Me.Items(bnd)
				// If clickedItem.Bounds.Contains(5, e.Y) Then
				// clickedItem.Selected = True
				// clickedItem.Focused = True
				// Exit For
				//End If
				//    Next
			}
		}
		base.OnMouseUp(e);
	}

	protected override void OnResize(System.EventArgs e)
	{
		this.Refresh();
		base.OnResize(e);
	}

	[DebuggerStepThrough()]

	protected override void OnDrawItem(System.Windows.Forms.DrawListViewItemEventArgs e)
	{
		if (!((e.State & ListViewItemStates.Selected) == 0) || e.Item.Selected) {
			using (Drawing.SolidBrush br = new Drawing.SolidBrush(_highlightColor)) {

				//Using br As New Drawing2D.LinearGradientBrush(e.Bounds, Color.FromArgb(200, Color.LightSkyBlue.R, Color.LightSkyBlue.B, Color.LightSkyBlue.G), Color.FromArgb(230, Color.Yellow.R, Color.Yellow.B, Color.Yellow.G), Drawing2D.LinearGradientMode.Vertical)
				// Draw the background for a selected item.
				e.Graphics.FillRectangle(br, e.Bounds);
				//e.DrawFocusRectangle()   'Disabled focus rectangle since it was off-center
			}
			//Else
			// Draw the background for an unselected item.
		}

		//Dim sf As New StringFormat()
		//Dim index As Integer
		//Dim clr As Color
		//
		//       index = SmallImageList.Images.IndexOfKey(e.Item.ImageKey)
		//       e.Graphics.DrawImage(SmallImageList.Images.Item(index), New Rectangle(e.Bounds.X + 2, e.Bounds.Y + 2, 16, 16))
		//       Using br As New SolidBrush(clr)
		// e.Graphics.DrawString(e.Item.Text, Me.Font, br, New Rectangle(e.Bounds.X + SmallImageList.ImageSize.Width + 4, e.Bounds.Y, e.Bounds.Width - SmallImageList.ImageSize.Width - 4, e.Bounds.Height), sf)
		// End Using

		//If Not DirectCast(e.Item.Tag, Users.FileData).FileExists Then
		//Using br2 As New Drawing.SolidBrush(Color.FromArgb(100, 255, 0, 0))
		// e.Graphics.FillRectangle(br2, e.Bounds)
		// End Using
		//End If

		// Draw the item text for views other than the Details view.
		if (!(this.View == View.Details)) {
			e.DrawText();
		}
		base.OnDrawItem(e);
	}

	//<DebuggerStepThrough()> _
	protected override void OnDrawSubItem(System.Windows.Forms.DrawListViewSubItemEventArgs e)
	{
		//Dim flags As TextFormatFlags = TextFormatFlags.Left

		StringFormat sf = new StringFormat();
		Color clr = default(Color);
		int index = 0;


		try {
			sf.LineAlignment = StringAlignment.Far;
			// Store the column text alignment, letting it default
			// to Left if it has not been set to Center or Right.
			switch (e.Header.TextAlign) {
				case HorizontalAlignment.Center:
					sf.Alignment = StringAlignment.Center;
					break;
				case HorizontalAlignment.Right:
					sf.Alignment = StringAlignment.Far;
					break;
			}

			e.Graphics.SmoothingMode = Drawing2D.SmoothingMode.AntiAlias;

			if (e.Item.ForeColor != _errorColor) {
				clr = this.ForeColor;
			} else {
				clr = _errorColor;
			}

			//Dim lv As ListViewItem = e.Item
			//Dim tmp As String
			//
			//            For Each t As ListViewItem.ListViewSubItem In e.Item.SubItems
			// tmp = t.Text
			// Next

			using (SolidBrush br = new SolidBrush(clr)) {
				if (e.Item.Text == e.SubItem.Text) {
					if (SmallImageList != null) {
						index = SmallImageList.Images.IndexOfKey(e.Item.ImageKey);
						if (index != -1) {
							e.Graphics.DrawImage(SmallImageList.Images.Item(index), new Rectangle(e.Bounds.X + 2, e.Bounds.Y + 2, 16, 16));
							e.Graphics.DrawString(e.Item.Text, this.Font, br, new Rectangle(e.Bounds.X + SmallImageList.ImageSize.Width + 4, e.Bounds.Y, e.Bounds.Width - SmallImageList.ImageSize.Width - 4, e.Bounds.Height), sf);
						} else {
							e.Graphics.DrawString(e.Item.Text, this.Font, br, new Rectangle(e.Bounds.X + 4, e.Bounds.Y, e.Bounds.Width - 4, e.Bounds.Height), sf);
						}
					} else {
						e.Graphics.DrawString(e.Item.Text, this.Font, br, new Rectangle(e.Bounds.X + 4, e.Bounds.Y, e.Bounds.Width - 4, e.Bounds.Height), sf);
					}
				} else {
					//e.DrawText()
					e.Graphics.DrawString(e.SubItem.Text, this.Font, br, e.Bounds, sf);
				}
			}

		//e.DrawText(flags)

		} finally {
			sf.Dispose();
		}

		//MyBase.OnDrawSubItem(e)
	}

	[DebuggerStepThrough()]
	protected override void OnDrawColumnHeader(System.Windows.Forms.DrawListViewColumnHeaderEventArgs e)
	{
		StringFormat sf = new StringFormat();

		try {
			// Store the column text alignment, letting it default
			// to Left if it has not been set to Center or Right.
			sf.LineAlignment = StringAlignment.Center;
			switch (e.Header.TextAlign) {
				case HorizontalAlignment.Center:
					sf.Alignment = StringAlignment.Center;
					break;
				case HorizontalAlignment.Right:
					sf.Alignment = StringAlignment.Far;
					break;
			}

			// Draw the standard header background.
			e.DrawBackground();

			// Draw the header text.
			Font headerFont = new Font("Microsoft Sans Serif", 8, FontStyle.Regular);
			try {
				e.Graphics.DrawString(e.Header.Text, headerFont, Brushes.Black, e.Bounds, sf);
			} finally {
				headerFont.Dispose();
			}

		} finally {
			sf.Dispose();
		}

		//MyBase.OnDrawColumnHeader(e)
	}

	protected override void OnMouseMove(System.Windows.Forms.MouseEventArgs e)
	{
		if (_redrawOnMouseMove) {
			ListViewItem item = this.GetItemAt(e.X, e.Y);
			//AndAlso item.Tag Is Nothing Then
			if (item != null) {
				this.Invalidate(item.Bounds);
				//item.Tag = "tagged"
			}
		}
		base.OnMouseMove(e);
	}

	protected override void OnInvalidated(System.Windows.Forms.InvalidateEventArgs e)
	{
		//Related to the use of Tag and RedrawOnMouseMove properties.

		//For Each item As ListViewItem In Me.Items
		//If item Is Nothing Then Return
		//item.Tag = Nothing
		//Next
		base.OnInvalidated(e);
	}

	protected override void OnColumnWidthChanged(System.Windows.Forms.ColumnWidthChangedEventArgs e)
	{
		this.Invalidate();
		base.OnColumnWidthChanged(e);
	}

	protected override void OnHandleCreated(System.EventArgs e)
	{
		base.OnHandleCreated(e);
		SendMessage(this.Handle.ToInt32, LVM_SETBKCOLOR, 0, CLR_NONE);
	}

	[DebuggerStepThrough()]
	protected override void WndProc(ref System.Windows.Forms.Message m)
	{
		switch (m.Msg) {
			case WM_VSCROLL:
				OnListViewScrolled(EventArgs.Empty);
				break;
			case WM_HSCROLL:
				OnListViewScrolled(EventArgs.Empty);
				break;
			case SBM_SETSCROLLINFO:
				OnListViewScrolled(EventArgs.Empty);
				break;
		}
		base.WndProc(m);
	}

	#endregion

	#region " Custom Methods "

	protected virtual void OnListViewScrolled(EventArgs e)
	{
		if (stp.IsRunning) {
			if (stp.ElapsedMilliseconds > _interval) {
				stp = Stopwatch.StartNew;
				this.Invalidate();
			}
		} else {
			stp.Start();
		}
		tmr.Stop();
		tmr.Start();
		if (ListViewScrolled != null) {
			ListViewScrolled(this, e);
		}
	}

	#endregion

	#endregion

	#region " Event Handlers "

	private void  // ERROR: Handles clauses are not supported in C#
tmr_Tick(object sender, System.EventArgs e)
	{
		this.Invalidate();
		tmr.Enabled = false;
	}

	#endregion

	#region " Events "

	public event ListViewScrolledEventHandler ListViewScrolled;
	public delegate void ListViewScrolledEventHandler(object sender, EventArgs e);

	#endregion

}