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Events and User Interaction

TreeDataGrid exposes lifecycle and interaction hooks for advanced behaviors.

Cell Lifecycle Events

  • CellPrepared: realized and ready for customization
  • CellClearing: being unrealized/recycled
  • CellValueChanged: value committed from edit interaction

Example:

grid.CellPrepared += (_, e) =>
{
    // e.Cell, e.ColumnIndex, e.RowIndex
};

grid.CellValueChanged += (_, e) =>
{
    // react to committed edits
};

Row Lifecycle Events

  • RowPrepared
  • RowClearing

Useful for row-level instrumentation.

Selection Intercept Hook

SelectionChanging can cancel selection updates:

grid.SelectionChanging += (_, e) =>
{
    if (ShouldBlockSelection())
        e.Cancel = true;
};

Drag/Drop Events

  • RowDragStarted
  • RowDragOver
  • RowDrop

See Drag and Drop Rows.

Retrieval Helpers

Use these APIs to resolve TreeDataGrid visuals or models from controls and indexes.

Resolve from Visual Element

  • TryGetRow(Control, out TreeDataGridRow?)
  • TryGetCell(Control, out TreeDataGridCell?)
  • TryGetRowModel<TModel>(Control, out TModel?)

Resolve by Visible Index

  • TryGetRow(int rowIndex)
  • TryGetCell(int columnIndex, int rowIndex)

Example:

if (grid.TryGetRow(10) is { } row)
{
    row.Focus();
}

Interaction Properties

Common behavior toggles:

  • CanUserSortColumns
  • CanUserResizeColumns
  • ShowColumnHeaders
  • AutoDragDropRows

Routed Events and Template Parts

Internally, control syncs row/header scroll viewers and delegates keyboard/pointer/text input to active selection interaction.

This means changing Source.Selection can materially change keyboard/pointer behavior without changing UI markup.

Troubleshooting

  • Feature behavior differs from expectations Cause: one or more options in this scenario are configured differently (source type, column options, sort/selection/edit state). Fix: compare your setup with the snippet in this article and verify runtime values on Source, Columns, and Selection.

  • Data changes are not visible in UI Cause: model or collection notifications are missing, or a replaced collection/source is not re-bound. Fix: ensure INotifyPropertyChanged/INotifyCollectionChanged flow is active and reassign Source after replacing underlying collections.

API Coverage Checklist