// *****************************************************************************
//
// © Component Factory Pty Ltd 2017. All rights reserved.
// The software and associated documentation supplied hereunder are the
// proprietary information of Component Factory Pty Ltd, 13 Swallows Close,
// Mornington, Vic 3931, Australia and are supplied subject to licence terms.
//
// Version 4.5.0.0 www.ComponentFactory.com
// *****************************************************************************
using System;
using System.Text;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Collections.Generic;
using System.Windows.Forms;
using System.Diagnostics;
namespace ComponentFactory.Krypton.Toolkit
{
/// <summary>
/// View element that draws a scrollbar.
/// </summary>
public class ViewDrawScrollBar : ViewLeaf
{
#region Instance Fields
private ScrollBar _scrollBar;
private bool _vertical;
private bool _removing;
private bool _shortSize;
private int _min;
private int _max;
private int _largeChange;
private int _smallChange;
private int _offset;
#endregion
#region Events
/// <summary>
/// Occurs when the scroll position has changed.
/// </summary>
public event EventHandler ScrollChanged;
#endregion
#region Identity
/// <summary>
/// Initialize a new instance of the ViewDrawScrollBar class.
/// </summary>
/// <param name="vertical">Is this a vertical scrollbar.</param>
public ViewDrawScrollBar(bool vertical)
{
// Remember the vertical/horizontal setting
_vertical = vertical;
//Default other properties
_removing = false;
_shortSize = false;
_min = 0;
_max = 100;
_largeChange = 20;
_smallChange = 1;
_offset = 0;
}
/// <summary>
/// Obtains the String representation of this instance.
/// </summary>
/// <returns>User readable name of the instance.</returns>
public override string ToString()
{
// Return the class name and instance identifier
return "ViewDrawScrollBar:" + Id;
}
/// <summary>
/// Release unmanaged and optionally managed resources.
/// </summary>
/// <param name="disposing">Called from Dispose method.</param>
protected override void Dispose(bool disposing)
{
// If called from explicit call to Dispose
if (disposing)
{
// Must remove the scroll bar resource
if (_scrollBar != null)
{
// Should never be called from garbage collector
Debug.Assert(!_scrollBar.InvokeRequired);
// Cannot destroy control in a different thread
if (!_scrollBar.InvokeRequired)
RemoveScrollBar();
}
}
base.Dispose(disposing);
}
#endregion
#region Vertical
/// <summary>
/// Gets and sets a value indicating if the scrollbar is vertical.
/// </summary>
public bool Vertical
{
get { return _vertical; }
set
{
// Only interested in changes
if (_vertical != value)
{
// Remember new orientation
_vertical = value;
// Remove the scrollbar as a child control
RemoveScrollBar();
}
}
}
#endregion
#region ShortSize
/// <summary>
/// Gets and sets a value indicating if the scroll should short size.
/// </summary>
public bool ShortSize
{
get { return _shortSize; }
set { _shortSize = value; }
}
#endregion
#region SetScrollValues
/// <summary>
/// Update the scrollbar with the latest scrolling values.
/// </summary>
/// <param name="min">Scroll minimum value.</param>
/// <param name="max">Scroll maximum value.</param>
/// <param name="smallChange">Size of a small change.</param>
/// <param name="largeChange">Size of a large change.</param>
/// <param name="offset">Current scrolling offset.</param>
public void SetScrollValues(int min,
int max,
int smallChange,
int largeChange,
int offset)
{
// Update cached values (applying limit checking)
_min = Math.Max(min, 0);
_max = Math.Max(max, 0);
_smallChange = Math.Max(smallChange, 0);
_largeChange = Math.Max(largeChange, 0);
_offset = Math.Max(offset, 0);
if (_scrollBar != null)
{
// Set the scrolling values
_scrollBar.Minimum = _min;
_scrollBar.Maximum = _max;
_scrollBar.SmallChange = _smallChange;
_scrollBar.LargeChange = _largeChange;
_scrollBar.Value = Math.Max(_min, Math.Min(_max, _offset));
}
}
#endregion
#region ScrollPosition
/// <summary>
/// Gets the current scroll position.
/// </summary>
public int ScrollPosition
{
get
{
if (_scrollBar != null)
return _scrollBar.Value;
else
return 0;
}
}
#endregion
#region Layout
/// <summary>
/// Discover the preferred size of the element.
/// </summary>
/// <param name="context">Layout context.</param>
public override Size GetPreferredSize(ViewLayoutContext context)
{
Debug.Assert(context != null);
// The minimum size is the minimum system size of a scrollbar
return new Size(SystemInformation.VerticalScrollBarWidth,
SystemInformation.HorizontalScrollBarHeight);
}
/// <summary>
/// Perform a layout of the elements.
/// </summary>
/// <param name="context">Layout context.</param>
public override void Layout(ViewLayoutContext context)
{
Debug.Assert(context != null);
// Prevent recreate of the control
if (!IsDisposed && !_removing)
{
// We take on all the available display area
ClientRectangle = context.DisplayRectangle;
// Are we allowed to layout child controls?
if (!context.ViewManager.DoNotLayoutControls)
{
// Make sure the scrollbar has actually been created
CreateScrollBar(context.Control);
// If we need to hide/disable the control then do it before position changes
if (!Visible) _scrollBar.Hide();
if (!Enabled) _scrollBar.Enabled = false;
// Should the scrollbar is shorter than then the entire client area?
if (ShortSize)
{
if (Vertical)
_scrollBar.SetBounds(ClientLocation.X, ClientLocation.Y,
ClientWidth, ClientHeight - SystemInformation.HorizontalScrollBarHeight);
else
_scrollBar.SetBounds(ClientLocation.X, ClientLocation.Y,
ClientWidth - SystemInformation.VerticalScrollBarWidth, ClientHeight);
}
else
{
// Position the ScrollBar in the entire requested area
_scrollBar.SetBounds(ClientLocation.X, ClientLocation.Y,
ClientWidth, ClientHeight);
}
// If we need to show/enable control then do it after position changes
if (Visible) _scrollBar.Show();
if (Enabled) _scrollBar.Enabled = true;
}
}
}
#endregion
#region Implementation
private void CreateScrollBar(Control parent)
{
// Do we need to create a scrollbar?
if (_scrollBar == null)
{
// Create the correct type of control
if (Vertical)
_scrollBar = new VScrollBar();
else
_scrollBar = new HScrollBar();
// Hook into scroll position changes
_scrollBar.Scroll += new ScrollEventHandler(OnScrollBarChange);
// Create it hidden
_scrollBar.Hide();
// Set the scrolling values
_scrollBar.Minimum = _min;
_scrollBar.Maximum = _max;
_scrollBar.SmallChange = _smallChange;
_scrollBar.LargeChange = _largeChange;
_scrollBar.Value = _offset;
// Add our new control to the provided parent collection
CommonHelper.AddControlToParent(parent, _scrollBar);
}
}
private void RemoveScrollBar()
{
// Do we need to remove the scrollbar?
if ((_scrollBar != null) && !_removing)
{
// Prevent recreate of the control during removal, as removing it
// will cause more layout cycles to occur. We put it back to false
// at the end of the remove process.
_removing = true;
// Unhook from events
_scrollBar.Scroll -= new ScrollEventHandler(OnScrollBarChange);
// Hide the scrollbar from view
_scrollBar.Hide();
// Remove scrollbar from containing collection
CommonHelper.RemoveControlFromParent(_scrollBar);
// Destroy the current scrollbar
_scrollBar.Dispose();
_scrollBar = null;
_removing = false;
}
}
private void OnScrollBarChange(object sender, ScrollEventArgs e)
{
// Update with the new scroll value
_scrollBar.Value = e.NewValue;
if (ScrollChanged != null)
ScrollChanged(this, EventArgs.Empty);
}
#endregion
}
}
