> For the complete documentation index, see [llms.txt](https://docs.grid.glideapps.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.grid.glideapps.com/extended-quickstart-guide/working-with-selections.md).

# Working with selections

Glide Data Grid selections are controlled via the [`gridSelection`](/api/dataeditor/selection-handling.md#gridselection) and [`onGridSelectionChanged`](/api/dataeditor/selection-handling.md#ongridselectionchange) properties. To respond to selection changes the gridSelection must be controlled.

```tsx
const [selection, setSelection] = React.useState<GridSelection>({
    columns: CompactSelection.empty(),
    rows: CompactSelection.empty(),
});

return <DataEditor
    {...otherProps}
    gridSelection={selection}
    onGridSelectionChange={setSelection}
/>
```

The [`GridSelection`](/api/common-types.md#gridselection) contains three different elements. The current selection, the selected rows, and the selected columns.

```tsx
interface GridSelection {
    readonly current?: {
        readonly cell: Item;
        readonly range: Readonly<Rectangle>;
        readonly rangeStack: readonly Readonly<Rectangle>[];
    };
    readonly columns: CompactSelection;
    readonly rows: CompactSelection;
}
```

The `current` part of the selection contains the selected `cell`. This is the item which will be drawn with a focus ring. The `range` represents the selected region around the cell that may be edited by certain commands such as delete. Finally, the `rangeStack` are additional ranges that the user has selected when [`multi-rect`](/api/dataeditor/selection-handling.md#column-range-rowselect) selection mode is enabled.

`rows` and `columns` are both a `CompactSelection`. A compact selection is a sparse array designed to efficiently hold spans of selected elements. They have the following interface:

```typescript
export class CompactSelection 
    static empty(): CompactSelection;
    static fromSingleSelection(selection: number | Slice): CompactSelection;
    
    public offset(amount: number): CompactSelection;
    public add(selection: number | Slice): CompactSelection;
    public remove(selection: number | Slice): CompactSelection;
    public first(): number | undefined;
    public last(): number | undefined;
    public hasIndex(index: number): boolean;
    public hasAll(index: Slice): boolean;
    public some(predicate: (index: number) => boolean): boolean;
    public equals(other: CompactSelection): boolean;
    public toArray(): number[];
    get length(): number;
    *[Symbol.iterator]()
}
```

In general, it is advisable not to call `toArray`. Iterating over the `CompactSelection` using a `for ... of` loop is significantly more efficient.


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.grid.glideapps.com/extended-quickstart-guide/working-with-selections.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.