DataGrid

Remarks

Virtualised in both directions, which is what doc 09 asks of this control by name and what makes it different from the tree. A hundred columns of a hundred thousand rows is ten million cells; what exists is the twenty-odd columns and thirty-odd rows that are on screen, and neither pool is rebuilt when the other scrolls.

⚠ Frozen columns are the leading n, not a flag on a column. Freezing an arbitrary subset raises a question with no good answer — what happens when a frozen column is dragged to the middle — and every grid that offers it ends up reordering the columns behind the user's back. FrozenColumns says how many stay put, and MoveColumn is what puts a column among them.

⚠ A frozen cell is positioned against the scroll offset, not against the content. The rows live inside the scroller, so everything in them moves left as the view scrolls right; a frozen cell adds the scroll offset back. That is one line and it is the entire mechanism — there is no second scroller and no second element tree.

⚠ Sorting and grouping are a view over the items, never a reorder of them. The list belongs to the caller, who is very likely iterating it elsewhere, and a grid that sorted in place would silently reorder a game's entity list because somebody clicked a column heading.

Fields and properties (19)

• public const int Overscan

  How many rows are realised above and below the viewport.

• protected override string TagName

  The element name this type answers to when a caller does not choose one.

• protected override bool AcceptsFocus

  Whether the focus can rest on this kind of control at all.

• public UiElement Header

  The strip of headings.

• public ScrollView Scroller

  The scroller the rows live in.

• public IReadOnlyList<DataColumn> Columns

  The columns, left to right.

• public IReadOnlyList<object> Items

  What is being shown.

• public IReadOnlyList<DataRow> Rows

  The rows that exist as elements, including the parked ones.

• public IReadOnlyList<DataHeaderCell> Headers

  The header cells that exist.

• public int RowCount

  How many lines the view has, group headers included.

• public IReadOnlyCollection<int> Selection

  Which items are selected, by their index in Items.

• public float RowHeight

  How tall a row is, from --row-height.

• public int FrozenColumns
• public bool MultiSelect
• public DataColumn? SortColumn

  Which column the view is sorted by, or null.

• public bool SortDescending

  Which way.

• public DataColumn? GroupColumn

  Which column the view is grouped by, or null.

• public static readonly UiPropertyKey FrozenColumnsProperty

  Identity for FrozenColumns.

• public static readonly UiPropertyKey MultiSelectProperty

  Identity for MultiSelect.

Events (3)

• public Action<DataGrid>? SelectionChanged

  Raised when the selection changes.

• public Action<DataGrid, object, DataColumn>? CellEdited

  Raised after an inline edit is committed.

• public Action<DataGrid, object>? Activated

  Raised when a row is double-clicked.

Methods (16)

• protected override void OnCreated()

  Builds whatever this element is made of, once, as it joins a document.

• public DataColumn AddColumn(string header, Func<object, object?>? value = null)

  Adds a column on the right.

• public DataColumn AddColumn(DataColumn column)

  Adds a column that was made elsewhere.

• public int IndexOf(DataColumn column)

  Where a column currently is, left to right.

• public void MoveColumn(int from, int to)

  Moves a column to another position.

• public void SetItems(IEnumerable<object> source)

  Shows a list of objects.

• public void SortBy(DataColumn? column, bool descending = false)

  Sorts the view by a column, or turns sorting off.

• public void GroupBy(DataColumn? column)

  Groups the view by a column, or turns grouping off.

• public void ToggleGroup(object key)

  Collapses or expands a group.

• public void Refresh()

  Rebuilds the view and realises the elements for it.

• public void Select(int item, ModifierKeys modifiers = None)

  Selects a row, or adds it to or removes it from the selection.

• public int RowIndexOf(int item)

  Which line of the view an item is on, or -1 if it is inside a collapsed group.

• public int ItemAt(int row)

  The item a line of the view shows, or -1 for a group header.

• public bool BeginEdit(DataCell cell)

  Puts a field in a cell so its value can be typed.

• public void ClearFrozenColumns()

  Unsets FrozenColumns, so it takes its default or its ancestor's value again.

• public void ClearMultiSelect()

  Unsets MultiSelect, so it takes its default or its ancestor's value again.

Used by (9)

• DataGridTestsVixen.Ui.Controls.Advanced.Tests
• BuildSettingsTestsVixen.Editor.App.Tests
• BuildSettingsViewVixen.Editor.App
• DeviceManagerViewVixen.Editor.Debugger
• DiagnosticsPanelTestsVixen.Editor.App.Tests
• KeyBindingsPanelTestsVixen.Editor.App.Tests
• KeyBindingsViewVixen.Editor.Ui
• PluginManagerViewVixen.Editor.App
• ProfilerViewVixen.Editor.Profiler