TreeDataGridRowSelectionModel<TModel> Class

Definition

Namespace:Avalonia.Controls.Selection

Assembly:Avalonia.Controls.TreeDataGrid

Package:Avalonia.Controls.TreeDataGrid

Implements row selection functionality for a Avalonia.Controls.TreeDataGrid control.

public class TreeDataGridRowSelectionModel<TModel>

Inheritance: object -> TreeDataGridSelectionModel -> TreeDataGridRowSelectionModel<TModel>

Implements: ag, ah

Remarks

TreeDataGridRowSelectionModel manages row selection in a TreeDataGrid, supporting both single and multiple selection modes. It tracks selection using Avalonia.Controls.IndexPath instances that represent positions in the hierarchical structure.

Row selection supports the following user interactions:

• Clicking on rows to select them
• Using arrow keys to navigate between rows
• Using Shift key to select ranges of rows
• Expanding and collapsing hierarchical rows with arrow keys
• Type-to-select functionality for quickly finding rows

Constructors

Name	Description
TreeDataGridRowSelectionModel<TModel>	No summary available.

TreeDataGridRowSelectionModel<TModel> Constructor

public TreeDataGridRowSelectionModel<TModel>(Avalonia.Controls.TreeDataGridSource<TModel><TModel> source)

Parameters

source Avalonia.Controls.TreeDataGridSource<TModel><TModel>

Methods

Name	Description
BatchUpdate	Creates a batch update operation that will defer selection change notifications until disposed.
BeginBatchUpdate	Begins a batch update of the selection.
Clear	Clears the selection.
Deselect	Deselects an item by its index in the source data.
EndBatchUpdate	Ends a batch update started by Avalonia.Controls.Selection.TreeDataGridRowSelectionModel<T>.BeginBatchUpdate.
IsSelected	Queries whether an item is currently selected.
Select	Selects an item by its index in the source data.
SelectAll	Selects all currently visible rows.
SelectRange	Selects an inclusive range of rows.

BatchUpdate Method

Creates a batch update operation that will defer selection change notifications until disposed.

public Avalonia.Controls.Selection.TreeDataGridRowSelectionModel<TModel>.BatchUpdateOperation<TModel><TModel> BatchUpdate()

Returns

Avalonia.Controls.Selection.TreeDataGridRowSelectionModel<TModel>.BatchUpdateOperation<TModel><TModel>

A disposable object that, when disposed, will commit the selection changes and raise appropriate events.

Remarks

Use this method with a using statement to group multiple selection operations together and raise only a single set of change events when the batch is complete. This is equivalent to calling Avalonia.Controls.Selection.TreeDataGridRowSelectionModel<T>.BeginBatchUpdate and Avalonia.Controls.Selection.TreeDataGridRowSelectionModel<T>.EndBatchUpdate.

BeginBatchUpdate Method

Begins a batch update of the selection.

public void BeginBatchUpdate()

Clear Method

Clears the selection.

public void Clear()

Deselect Method

Deselects an item by its index in the source data.

public void Deselect(Avalonia.Controls.IndexPath index)

Parameters

index Avalonia.Controls.IndexPath

The index into the source data.

EndBatchUpdate Method

Ends a batch update started by Avalonia.Controls.Selection.TreeDataGridRowSelectionModel<T>.BeginBatchUpdate.

public void EndBatchUpdate()

IsSelected Method

Queries whether an item is currently selected.

public bool IsSelected(Avalonia.Controls.IndexPath index)

Parameters

index Avalonia.Controls.IndexPath

The index of the item in the source data.

Returns

bool

True if the item is selected; otherwise false.

Select Method

Selects an item by its index in the source data.

public void Select(Avalonia.Controls.IndexPath index)

Parameters

index Avalonia.Controls.IndexPath

The index path of the item to select.

SelectAll Method

Selects all currently visible rows.

public void SelectAll()

Remarks

Only rows that are currently materialized in the source (i.e. visible, taking into account the expanded/collapsed state of parent rows) are selected; descendants of collapsed rows are not selected. This method does nothing when Avalonia.Controls.Selection.TreeDataGridSelectionModel.SingleSelect is true.

SelectRange Method

Selects an inclusive range of rows.

public void SelectRange(Avalonia.Controls.IndexPath start, Avalonia.Controls.IndexPath end)

Parameters

start Avalonia.Controls.IndexPath

The index of the row at which the range starts.

end Avalonia.Controls.IndexPath

The index of the row at which the range ends.

Remarks

The range is selected by iterating the currently visible rows between start and end; any existing selection is cleared first. This method does nothing when Avalonia.Controls.Selection.TreeDataGridSelectionModel.SingleSelect is true.

Properties

Name	Description
AnchorIndex	Gets or sets the anchor index.
Count	No summary available.
IsCellSelectionModel	Gets a value indicating whether this is a cell selection model.
RangeAnchorIndex	Gets or sets the range anchor index.
SelectedIndex	Gets or sets the selected index within the data.
SelectedIndexes	Gets the indexes of the selected items.
SelectedItem	Gets the currently selected item.
SelectedItems	Gets a collection containing all selected items.
SingleSelect	Gets or sets a value indicating whether only a single item can be selected at a time.
Source	Gets the data source for the selection model.

AnchorIndex Property

Gets or sets the anchor index.

public Avalonia.Controls.IndexPath AnchorIndex { get; set; }

Remarks

The anchor index is the moving end of the selection: the item that keyboard navigation acts on. Pressing an arrow key navigates relative to this index, and a non-range selection updates it to the newly selected item. It is distinct from Avalonia.Controls.Selection.TreeDataGridRowSelectionModel<T>.RangeAnchorIndex, which is the fixed pivot that a range extends from.

For example, after selecting the range 1 to 3 (by clicking item 1 then Shift-clicking item 3, or by calling Avalonia.Controls.Selection.TreeDataGridRowSelectionModel<T>.SelectRange(Avalonia.Controls.IndexPath,Avalonia.Controls.IndexPath)), Avalonia.Controls.Selection.TreeDataGridRowSelectionModel<T>.RangeAnchorIndex is 1 (the pivot) while Avalonia.Controls.Selection.TreeDataGridRowSelectionModel<T>.AnchorIndex is 3 (the moving end). A subsequent Shift+Up then recomputes the range from the pivot 1 to the new end 2.

Count Property

public int Count { get; set; }

IsCellSelectionModel Property

Gets a value indicating whether this is a cell selection model.

public bool IsCellSelectionModel { get; set; }

RangeAnchorIndex Property

Gets or sets the range anchor index.

public Avalonia.Controls.IndexPath RangeAnchorIndex { get; set; }

Remarks

The range anchor index is the fixed pivot from which a range selection extends. It is set when a fresh selection begins (for example when Avalonia.Controls.Selection.TreeDataGridRowSelectionModel<T>.SelectedIndex is set, or to the anchor argument of Avalonia.Controls.Selection.TreeDataGridRowSelectionModel<T>.SelectRange(Avalonia.Controls.IndexPath,Avalonia.Controls.IndexPath)) and is preserved while the range is extended, so that repeated Shift-click or Shift+arrow operations all extend from the same point.

Unlike Avalonia.Controls.Selection.TreeDataGridRowSelectionModel<T>.AnchorIndex, it is not moved by a plain Avalonia.Controls.Selection.TreeDataGridRowSelectionModel<T>.Select(Avalonia.Controls.IndexPath) call or by extending a range; only by operations that start a new selection.

SelectedIndex Property

Gets or sets the selected index within the data.

public Avalonia.Controls.IndexPath SelectedIndex { get; set; }

SelectedIndexes Property

Gets the indexes of the selected items.

public System.Collections.Generic.IReadOnlyList<Avalonia.Controls.IndexPath> SelectedIndexes { get; set; }

SelectedItem Property

Gets the currently selected item.

public TModel SelectedItem { get; set; }

Value

The selected item, or default(TModel) if no item is selected.

Remarks

When multiple items are selected, this property returns the first selected item.

SelectedItems Property

Gets a collection containing all selected items.

public System.Collections.Generic.IReadOnlyList<TModel> SelectedItems { get; set; }

Value

A read-only list of the selected items.

SingleSelect Property

Gets or sets a value indicating whether only a single item can be selected at a time.

public bool SingleSelect { get; set; }

Source Property

Gets the data source for the selection model.

public System.Collections.IEnumerable Source { get; set; }

Events

Name	Description
SelectionChanged	Occurs when the selection changes.
IndexesChanged	Occurs when item indexes change due to insertions or removals in the data source. Inherited from TreeDataGridSelectionModel.
PropertyChanged	Inherited from TreeDataGridSelectionModel.
SourceReset	Occurs when the data source is reset. Inherited from TreeDataGridSelectionModel.

SelectionChanged Event

Occurs when the selection changes.

public event EventHandler<Avalonia.Controls.Selection.TreeDataGridSelectionChangedEventArgs<T><TModel>> SelectionChanged

Remarks

This event provides strongly-typed access to the selection changes, including the items and index paths that were selected and deselected.