Class TreeState<T>

Namespace

MiniTui

Assembly

MiniTui.dll

The rows, expanded nodes, selection and scroll offset of a tree (1.x spec §11), drawn with Tree<T>(TreeState<T>). T is the app's own node type: the state asks for each expanded node's children instead of holding a copy of the tree.

public sealed class TreeState<T> where T : class

Type Parameters

T

Inheritance

object

TreeState<T>

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.ReferenceEquals(object, object)

object.ToString()

Constructors

TreeState(Func<T, IReadOnlyList<T>>, Func<T, string>, IEqualityComparer<T>?)

Create a state.

public TreeState(Func<T, IReadOnlyList<T>> children, Func<T, string> text, IEqualityComparer<T>? comparer = null)

Parameters

children Func<T, IReadOnlyList<T>>

A node's children. Asked for only while the node is expanded.

text Func<T, string>

A node's label: drawn by default, and searched by type-ahead.

comparer IEqualityComparer<T>

How nodes are matched, for the expanded set and the selection.

Properties

Checkboxes

Draw a check box on each row, toggled by Space and a click on it (1.x spec §18.5). Off by default.

public bool Checkboxes { get; set; }

Property Value

bool

CheckedNodes

The checked nodes in tree order: each checked node without children and each parent whose descendants are all checked, without what's under it.

public IReadOnlyList<T> CheckedNodes { get; }

Property Value

IReadOnlyList<T>

Filter

Show only the nodes this matches and their ancestors, drawn open so the matches show (1.x spec §18.4). The children of every node are read, expanded or not. ← and the expander can still close a node while filtering; that's forgotten when the filter changes, and the expanded nodes aren't touched. Null shows the whole tree.

public Func<T, bool>? Filter { get; set; }

Property Value

Func<T, bool>

HasChildren

Whether a node can expand, without reading its children; drawn as an expander. By default, whether its children aren't empty. Set it when reading children is slow, or to show an expander before they're loaded.

public Func<T, bool>? HasChildren { get; set; }

Property Value

Func<T, bool>

Offset

The first visible row. Adjusted when drawn so Selected is visible after the selection moves; the wheel and the scrollbar scroll without moving the selection (1.x spec §14.4).

public int Offset { get; set; }

Property Value

int

Roots

The top-level nodes. Setting them keeps the expanded nodes and the selection where they still match.

public IReadOnlyList<T> Roots { get; set; }

Property Value

IReadOnlyList<T>

Rows

The rows the tree shows: every root and, depth first, the children of each expanded node. Computed when drawn, on each key and mouse event, and when the roots or the expanded nodes change (1.x spec §11.4).

public IReadOnlyList<TreeRow<T>> Rows { get; }

Property Value

IReadOnlyList<TreeRow<T>>

Selected

The selected node, or null for none (the first row is selected when the rows are next computed). Setting it doesn't raise SelectionChanged or expand anything; a node that isn't in Rows is replaced when the rows are next computed.

public T? Selected { get; set; }

Property Value

T

ViewportHeight

How many rows were visible at the last draw. Used by PgUp and PgDn.

public int ViewportHeight { get; }

Property Value

int

Methods

Collapse(T)

Collapse a node. If the selection was inside it, the node is selected.

public void Collapse(T node)

Parameters

node T

CollapseAll()

Collapse every node.

public void CollapseAll()

Expand(T)

Expand a node. Does nothing for a node without children or one already expanded.

public void Expand(T node)

Parameters

node T

ExpandAll()

Expand every node that has children. This reads the whole tree.

public void ExpandAll()

HandleKey(ConsoleKeyInfo)

Handle ↑ ↓ PgUp PgDn Home End, → (expand, or the first child), ← (collapse, or the parent), Enter (toggle, or Activated on a leaf) and type-ahead.

public bool HandleKey(ConsoleKeyInfo key)

Parameters

key ConsoleKeyInfo

Returns

bool

True if the key was one of these.

HandleMouse(MouseEvent)

Handle the mouse over the tree drawn last: the wheel scrolls by one row, a left press on a row selects it and, on its expander, also toggles it, and the scrollbar's thumb drags and its track pages (1.x spec §14.4). A double-click on a row activates it as Enter does: a leaf raises Activated, a parent expands or collapses (§17.4). Scrolling doesn't move the selection.

public bool HandleMouse(MouseEvent mouse)

Parameters

mouse MouseEvent

Returns

bool

True if the event did any of these.

IsChecked(T)

Whether a node is checked: for a node with children, true when they're all checked, false when none is, and null when some are; for one without (or with none loaded), whether it was checked.

public bool? IsChecked(T node)

Parameters

node T

Returns

bool?

IsExpanded(T)

Whether node is expanded.

public bool IsExpanded(T node)

Parameters

node T

Returns

bool

Reload(T)

Forget a node's loaded children (and cancel a load that's running), so they load again when it's next expanded, or now if it's expanded. Does nothing for a state without a loader.

public void Reload(T node)

Parameters

node T

Reveal(IReadOnlyList<T>)

Expand each node of path but the last, select the last, and scroll it into view at the next draw (1.x spec §18.3). The path starts at a root, and each node must be among the previous one's children.

public bool Reveal(IReadOnlyList<T> path)

Parameters

path IReadOnlyList<T>

Returns

bool

False, changing nothing, when the path doesn't match the tree or the filter hides its last node.

RevealAsync(IReadOnlyList<T>, CancellationToken)

As Reveal(IReadOnlyList<T>), after loading the children of each node on the path that aren't loaded yet, for a state from Async<T>(Func<T, CancellationToken, Task<IReadOnlyList<T>>>, Func<T, string>, IEqualityComparer<T>?) (1.x spec §18.3). Without a loader it's Reveal(IReadOnlyList<T>).

public Task<bool> RevealAsync(IReadOnlyList<T> path, CancellationToken cancellationToken = default)

Parameters

path IReadOnlyList<T>

cancellationToken CancellationToken

Returns

Task<bool>

False when the path doesn't match the tree (as far as it loaded) or the filter hides its node.

SetChecked(T, bool)

Check or uncheck a node and everything under it, and raise CheckedChanged.

public void SetChecked(T node, bool isChecked)

Parameters

node T

isChecked bool

Toggle(T)

Expand a collapsed node or collapse an expanded one.

public void Toggle(T node)

Parameters

node T

Events

Activated

Raised when Enter is pressed on a node without children.

public event EventHandler<TreeNodeEventArgs<T>>? Activated

Event Type

EventHandler<TreeNodeEventArgs<T>>

CheckedChanged

Raised when Space, a click or SetChecked(T, bool) checks or unchecks a node (the one toggled).

public event EventHandler<TreeNodeEventArgs<T>>? CheckedChanged

Event Type

EventHandler<TreeNodeEventArgs<T>>

Collapsed

Raised when a node collapses, from a key, a click or code.

public event EventHandler<TreeNodeEventArgs<T>>? Collapsed

Event Type

EventHandler<TreeNodeEventArgs<T>>

Expanded

Raised when a node expands, from a key, a click or code. Lazy loaders start loading here.

public event EventHandler<TreeNodeEventArgs<T>>? Expanded

Event Type

EventHandler<TreeNodeEventArgs<T>>

SelectionChanged

Raised on the UI thread when the user moves the selection (not when code sets it).

public event EventHandler? SelectionChanged

Event Type

EventHandler