/// <summary>
/// Initializes a new instance of the <see cref="MenuDisplay{T}"/> class.
/// </summary>
/// <param name="point">The point where the menu should be displayed.</param>
/// <param name="displayedLines">
/// The maximum number of console lines the menu display should use.
/// The menu can display more options than this value.
/// Values greater than the height of the console can result in odd effects.</param>
public MenuDisplay(IConsole console, ConsolePoint point, int displayedLines)
{
_console = console ?? throw new ArgumentNullException(nameof(console));
_windowOrigin = _console.GetWindowPosition();
_origin = point;
_options = new MenuOptionCollection <TOption>();
_options.CollectionChanged += OptionsCollectionChanged;
_displayed = new List <ConsoleString>();
for (int i = 0; i < displayedLines; i++)
{
_displayed.Add("");
}
_displayOffset = 0;
_index = -1;
_prompt = "> ";
_noPrompt = " ";
_prefixTop = new PrefixKeyCollection();
_prefixBottom = new PrefixKeyCollection();
_hasPrefix = false;
_prefixTop.PrefixSetChanged += UpdateAllOptions;
_prefixBottom.PrefixSetChanged += UpdateAllOptions;
}
private void OptionsCollectionChanged(MenuOptionCollection <TOption> collection, CollectionUpdateTypes updateType, int index, int count)
{
switch (updateType)
{
case CollectionUpdateTypes.Clear:
_displayOffset = 0;
_index = -1;
UpdateAllOptions();
break;
case CollectionUpdateTypes.Insert:
{
if (index <= SelectedIndex)
{
SelectedIndex += count;
}
var from = Math.Max(Math.Min(index, _options.Count - PrefixesBottom.Count - 1), 0);
for (int i = from; i < _options.Count; i++)
{
UpdateOption(i);
}
}
break;
case CollectionUpdateTypes.Remove:
{
var from = Math.Max(Math.Min(index, _options.Count - PrefixesBottom.Count - 1), 0);
var newOffset = Math.Max(0, _options.Count - _displayed.Count);
if (newOffset < _displayOffset)
{
from = Math.Max(from - _displayOffset + newOffset, 0);
_displayOffset = newOffset;
}
for (int i = from; i < _options.Count; i++)
{
UpdateOption(i);
}
UpdateOption(_options.Count);
if (index < SelectedIndex || _options.Count == SelectedIndex)
{
SelectedIndex -= count;
}
}
break;
case CollectionUpdateTypes.Replace:
if (_index >= index && _index < index + count)
{
_index = -1;
}
for (int i = 0; i < count; i++)
{
UpdateOption(i + index);
}
break;
case CollectionUpdateTypes.Update:
for (int i = 0; i < count; i++)
{
UpdateOption(i + index);
}
break;
}
}
