public ListPromptState <T> Show(ListPromptTree <T> tree, int requestedPageSize = 15)
{
if (tree is null)
{
throw new ArgumentNullException(nameof(tree));
}
if (!_console.Profile.Capabilities.Interactive)
{
throw new NotSupportedException(
"Cannot show selection prompt since the current " +
"terminal isn't interactive.");
}
if (!_console.Profile.Capabilities.Ansi)
{
throw new NotSupportedException(
"Cannot show selection prompt since the current " +
"terminal does not support ANSI escape sequences.");
}
var nodes = tree.Traverse().ToList();
var state = new ListPromptState <T>(nodes, _strategy.CalculatePageSize(_console, nodes.Count, requestedPageSize));
var hook = new ListPromptRenderHook <T>(_console, () => BuildRenderable(state));
using (new RenderHookScope(_console, hook))
{
_console.Cursor.Hide();
hook.Refresh();
while (true)
{
var key = _console.Input.ReadKey(true);
var result = _strategy.HandleInput(key, state);
if (result == ListPromptInputResult.Submit)
{
break;
}
if (state.Update(key.Key) || result == ListPromptInputResult.Refresh)
{
hook.Refresh();
}
}
}
hook.Clear();
_console.Cursor.Show();
return(state);
}
private IRenderable BuildRenderable(ListPromptState <T> state)
{
var pageSize = state.PageSize;
var middleOfList = pageSize / 2;
var skip = 0;
var take = state.ItemCount;
var cursorIndex = state.Index;
var scrollable = state.ItemCount > pageSize;
if (scrollable)
{
skip = Math.Max(0, state.Index - middleOfList);
take = Math.Min(pageSize, state.ItemCount - skip);
if (state.ItemCount - state.Index < middleOfList)
{
// Pointer should be below the end of the list
var diff = middleOfList - (state.ItemCount - state.Index);
skip -= diff;
take += diff;
cursorIndex = middleOfList + diff;
}
else
{
// Take skip into account
cursorIndex -= skip;
}
}
// Build the renderable
return(_strategy.Render(
_console,
scrollable, cursorIndex,
state.Items.Skip(skip).Take(take)
.Select((node, index) => (index, node))));
}
/// <inheritdoc/>
ListPromptInputResult IListPromptStrategy <T> .HandleInput(ConsoleKeyInfo key, ListPromptState <T> state)
{
if (key.Key == ConsoleKey.Enter || key.Key == ConsoleKey.Spacebar)
{
// Selecting a non leaf in "leaf mode" is not allowed
if (state.Current.IsGroup && Mode == SelectionMode.Leaf)
{
return(ListPromptInputResult.None);
}
return(ListPromptInputResult.Submit);
}
return(ListPromptInputResult.None);
}
/// <inheritdoc/>
ListPromptInputResult IListPromptStrategy <T> .HandleInput(ConsoleKeyInfo key, ListPromptState <T> state)
{
if (key.Key == ConsoleKey.Enter)
{
if (Required && state.Items.None(x => x.Selected))
{
// Selection not permitted
return(ListPromptInputResult.None);
}
// Submit
return(ListPromptInputResult.Submit);
}
if (key.Key == ConsoleKey.Spacebar)
{
var current = state.Items[state.Index];
var select = !current.Selected;
if (Mode == SelectionMode.Leaf)
{
// Select the node and all it's children
foreach (var item in current.Traverse(includeSelf: true))
{
item.Selected = select;
}
// Visit every parent and evaluate if it's selection
// status need to be updated
var parent = current.Parent;
while (parent != null)
{
parent.Selected = parent.Traverse(includeSelf: false).All(x => x.Selected);
parent = parent.Parent;
}
}
else
{
current.Selected = !current.Selected;
}
// Refresh the list
return(ListPromptInputResult.Refresh);
}
return(ListPromptInputResult.None);
}