Tree view

Use lcsTreeView for anything nested: document folders, product categories, teams and their people, a site's pages. Power Apps has no tree control, and the usual workaround nests galleries inside galleries, which is slow and stops at two levels. This component:

• Draws the whole tree in one gallery, from one flat table: each node names its ParentKey.
• Reads at a glance: a card with a title, thin guide lines that join each level to its parent, folders in amber and files in your colour, and how many items each folder holds.
• Opens and closes nodes with a chevron.
• Loads children only when needed: mark a node HasChildren: true without giving its children, and load them in OnExpand(NodeKey). The tree shows them as soon as they arrive.
• Marks the selected node (a tint, a filled icon and bold text) and runs OnNodeSelect(NodeKey).
• Remembers what's open as ExpandedKeys, so you can save it and open the same nodes next time.
• Goes up to five levels deep, with your AccentColor, a Dark theme and two looks: Standard (a soft highlight for the selected node) and Premium (a solid pill in your colour and a soft shadow).

The examples call it treeDocs on your screen.

Give it your nodes as one table. ParentKey is blank for the top level:

// treeDocs.Nodes
ForAll(
    colFolders,
    {
        Key: Text(ID),
        ParentKey: If(IsBlank(ParentFolder), "", Text(ParentFolder.Id)),
        Label: Title,
        Icon: If(IsFolder, "Folder", "Document"),
        HasChildren: IsFolder
    }
)

Open what the user selects:

// treeDocs.OnNodeSelect
Set(gblFolder, LookUp(colFolders, Text(ID) = NodeKey))

Load a folder's children the first time it opens:

// treeDocs.OnExpand
If(
    IsEmpty(Filter(colFolders, Text(ParentFolder.Id) = NodeKey)),
    Collect(colFolders, Filter(Folders, ParentFolder.Id = Value(NodeKey)))
)

Open the same nodes as last time:

// App.OnStart
Set(gblOpenFolders, Coalesce(LookUp(Settings, Name = "OpenFolders").Value, ""))

// treeDocs.DefaultExpandedKeys
gblOpenFolders

// Wherever you save: the nodes open now
Patch(Settings, LookUp(Settings, Name = "OpenFolders"), { Value: treeDocs.ExpandedKeys })

Show where something is, with the actions:

// A button: open its folders, then select it
treeDocs.Expand("docs");
treeDocs.Expand("plans");
Set(gblCurrent, "q3")

// treeDocs.CurrentKey
gblCurrent

A folder tree in Dataverse is usually a table with a lookup to itself, such as Folders with a Parent Folder lookup to Folders. The row's unique identifier is the column named after the table (Folder), and a lookup gives its row's, so the keys are their text:

// Screen1.OnVisible: the top level
ClearCollect(colFolders, Filter(Folders, 'Parent Folder' = Blank()))

// treeDocs.Nodes
ForAll(
    colFolders,
    {
        Key: Text(Folder),
        ParentKey: If(IsBlank('Parent Folder'), "", Text('Parent Folder'.Folder)),
        Label: Name,
        Icon: "Folder",
        HasChildren: true
    }
)

// treeDocs.OnExpand: a folder's children, the first time it opens
If(
    IsEmpty(Filter(colFolders, Text('Parent Folder'.Folder) = NodeKey)),
    Collect(colFolders, Filter(Folders, 'Parent Folder'.Folder = GUID(NodeKey)))
)

Loading each level as it opens keeps every query on the server, so a large tree isn't cut off at 500 rows.

• Each node is a button named by its label and level ("Plans, level 2"). Its chevron is a separate button that says what it does ("Expand Plans", "Collapse Plans").
• The selected node has a tint, a filled icon and bold text, so colour is never the only signal.
• All the words screen readers hear are inputs (ExpandText, CollapseText, LevelText, TreeLabel), for your language.
• With Motion on (the default), a node's highlight eases in from the left when it's selected and a chevron turns as its folder opens or closes, each in a third of a second or less. None plays for people who've asked their device for reduced motion, and Motion set to false changes them at once, as in 0.1.0.

• Up to five levels. Deeper nodes don't show.
• The arrow keys don't move through the tree. Canvas components can't read key presses, so Tab moves from button to button.
• Nodes needs all five columns, with HasChildren true or false.
• ExpandAll() opens nodes whose children are already in Nodes. It doesn't run OnExpand, so it won't load children that aren't loaded yet.
• Up to 999 children under one node keep their order.

• 0.2.0: motion: the selected node's highlight eases in and a chevron turns when its folder opens or closes (skipped for reduced motion); a Motion input turns it off. With Motion off, it's exactly 0.1.0.
• 0.1.0: first version: one flat table, open and close, children loaded through OnExpand, selection, ExpandedKeys, and the Expand, Collapse, ExpandAll and CollapseAll actions.