Extended Cursors for .Net

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.ComponentModel.Design;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Windows.Forms.Design;

namespace ExtCursors.Design
{
    #region "Class : ExtCursorSelectDropDown"
    //=========================================================================
    //=========================================================================
    [ToolboxItem(false)]
    public partial class ExtCursorSelectDropDown : UserControl
    {
        private ITypeDescriptorContext _Context = null;
        private IWindowsFormsEditorService _EditorService;
        private bool _InternalResizing = false;
        private static int _PreferredHeight = -1;
        private Size _CursorSize;
        private int _TextHeight = -1;
        private bool _MouseDown = false;
        private object _CurrentValue = null;
        internal ExtCursor _SelectedValue = null;
        internal bool _Cancelled = true;
        private StringFormat _StringFormat;

        //=========================================================================
        public ExtCursorSelectDropDown(ITypeDescriptorContext pContext, IWindowsFormsEditorService pEditorService, object pCurrentValue)
        {
            _Context = pContext;
            _EditorService = pEditorService;
            _CurrentValue = pCurrentValue;
            _Cancelled = true;
            _MouseDown = false;
            _StringFormat = new StringFormat(StringFormatFlags.NoWrap);
            _StringFormat.Trimming = StringTrimming.EllipsisCharacter;
            _StringFormat.Alignment = StringAlignment.Near;
            _StringFormat.LineAlignment = StringAlignment.Center;
            _TextHeight = -1;

            InitializeComponent();

            // get the size of a cursor...
            Cursor TestCursor = System.Windows.Forms.Cursors.Arrow;
            _CursorSize = TestCursor.Size;
            this.listBox_ExtCursors.ItemHeight = _CursorSize.Height + 5;
            this.listBox_ExtCursors.BeginUpdate();
            // add the (none) option...
            this.listBox_ExtCursors.Items.Add(new object());
            int SelIndex = 0;
            // add the ExtCursors...
            int Idx;
            if (_Context != null)
            {
                if (_Context.Container != null)
                {
                    try
                    {
                        // get the top container (the form) - because that's where the ExtCursor components live...
                        IDesignerHost DesignerHost = (IDesignerHost)_Context.GetService(typeof(IDesignerHost));
                        IContainer TopContainer = DesignerHost.RootComponent.Site.Container;
                        foreach (object Ctrl in TopContainer.Components)
                        {
                            if (Ctrl is ExtCursor)
                            {
                                Idx = this.listBox_ExtCursors.Items.Add(Ctrl);
                                if (Ctrl == _CurrentValue)
                                {
                                    SelIndex = Idx;
                                }
                            }
                        }
                    }
                    catch
                    {
                        // swallow exceptions
                        // feedback (i.e. MessageBox) could cause more problems
                        // worst case - dropdown list empty or partially filled
                    }
                }
            }
            Graphics gfx = null;
            try
            {
                gfx = Graphics.FromHwnd(this.Handle);
                SizeF TxtSize = gfx.MeasureString("([Hg", this.listBox_ExtCursors.Font);
                _TextHeight = System.Convert.ToInt32(TxtSize.Height);
                gfx.Dispose();
            }
            catch
            {
                _TextHeight = 16;
            }
            finally
            {
                if (gfx != null)
                {
                    gfx.Dispose();
                }
            }
            this.listBox_ExtCursors.SelectedIndex = SelIndex;
            this.listBox_ExtCursors.EndUpdate();
            _InternalResizing = true;
            int ItemsCount = Math.Min(this.listBox_ExtCursors.Items.Count, 9);
            if ((ExtCursorSelectDropDown._PreferredHeight == -1) || (ItemsCount == 1))
            {
                // resize according to the number of items...
                int ItemHeight = Math.Max(_CursorSize.Height + 5, _TextHeight + 2);
                this.ClientSize = new Size(this.ClientSize.Width, (_TextHeight + 2) + ((ItemsCount - 1) * ItemHeight));
            }
            else
            {
                this.ClientSize = new Size(this.ClientSize.Width, ExtCursorSelectDropDown._PreferredHeight);
            }
            _InternalResizing = false;
        }

        //=========================================================================
        private void ExtCursorSelectDropDown_PreviewKeyDown(object sender, PreviewKeyDownEventArgs e)
        {
            if (e.KeyCode == Keys.Return)
            {
                _Cancelled = false;
            }
        }

        //=========================================================================
        private void listBox_ExtCursors_MeasureItem(object sender, MeasureItemEventArgs e)
        {
            if (_TextHeight == -1)
            {
                SizeF TxtSize = e.Graphics.MeasureString("([Hg", this.listBox_ExtCursors.Font);
                _TextHeight = System.Convert.ToInt32(TxtSize.Height);
            }
            if (e.Index == 0)
            {
                e.ItemHeight = _TextHeight + 2;
            }
            else
            {
                e.ItemHeight = Math.Max(_CursorSize.Height + 5, _TextHeight + 2);
            }
        }

        //=========================================================================
        private void listBox_ExtCursors_DrawItem(object sender, DrawItemEventArgs e)
        {
            if (e.Index > -1)
            {
                Brush TextBrush = SystemBrushes.WindowText;
                Rectangle TextRect;
                if ((e.State & DrawItemState.Selected) == DrawItemState.Selected)
                {
                    e.Graphics.FillRectangle(SystemBrushes.Highlight, e.Bounds);
                    TextBrush = SystemBrushes.HighlightText;
                }
                else
                {
                    e.Graphics.FillRectangle(SystemBrushes.Window, e.Bounds);
                }
                if (e.Index == 0)
                {
                    // draw none...
                    TextRect = new Rectangle(new Point(e.Bounds.X + 2, e.Bounds.Y), new Size(e.Bounds.Width - 2, e.Bounds.Height));
                    e.Graphics.DrawString("(none)", this.listBox_ExtCursors.Font, TextBrush, TextRect, _StringFormat);
                }
                else
                {
                    ExtCursor ThisCursor = (ExtCursor)this.listBox_ExtCursors.Items[e.Index];
                    Rectangle CursorRect = new Rectangle(new Point(e.Bounds.X + 2, e.Bounds.Y + 2), _CursorSize);
                    e.Graphics.FillRectangle(SystemBrushes.ControlLight, CursorRect);
                    e.Graphics.DrawRectangle(SystemPens.WindowText, CursorRect);
                    if (ThisCursor._Cursor != null)
                    {
                        ThisCursor._Cursor.DrawStretched(e.Graphics, CursorRect);
                    }
                    TextRect = new Rectangle(new Point(e.Bounds.X + _CursorSize.Width + 5, e.Bounds.Y), new Size(e.Bounds.Width - (_CursorSize.Width + 5), e.Bounds.Height));
                    e.Graphics.DrawString(ThisCursor.Site.Name, this.listBox_ExtCursors.Font, TextBrush, TextRect, _StringFormat);
                }
            }
        }

        //=========================================================================
        private void listBox_ExtCursors_MouseDoubleClick(object sender, MouseEventArgs e)
        {
            _MouseDown = true;
        }

        //=========================================================================
        private void listBox_ExtCursors_MouseDown(object sender, MouseEventArgs e)
        {
            _MouseDown = true;
        }

        //=========================================================================
        private void listBox_ExtCursors_MouseUp(object sender, MouseEventArgs e)
        {
            _MouseDown = false;
        }

        //=========================================================================
        private void listBox_ExtCursors_SelectedValueChanged(object sender, EventArgs e)
        {
            if (this.listBox_ExtCursors.SelectedIndex != -1)
            {
                if (this.listBox_ExtCursors.SelectedIndex == 0)
                {
                    _SelectedValue = null;
                }
                else
                {
                    _SelectedValue = (ExtCursor)this.listBox_ExtCursors.Items[this.listBox_ExtCursors.SelectedIndex];
                }
                if (_MouseDown)
                {
                    _Cancelled = false;
                    _EditorService.CloseDropDown();
                }
            }
        }

        //=========================================================================
        private void ExtCursorSelectDropDown_Resize(object sender, EventArgs e)
        {
            if (!_InternalResizing && (this.listBox_ExtCursors.Items.Count > 1))
            {
                ExtCursorSelectDropDown._PreferredHeight = this.ClientSize.Height;
            }
        }


    }
    #endregion
}