# Selection

The DataGrid provides a selection functionality, which allows the user to select one or more rows and/or cells from the data displayed by the component.

## Selection Modes

The DataGrid provides the following selection modes, which allow you to manipulate the type of selection. To control the modes, use the `SelectionMode` property, which accepts the following values:

* (Default) `Single`—A single unit may be selected.
* `Multiple`—Multiple units can be selected.
* `Extended`—Items are added to the selection only by combining the mouse clicks with the `Ctrl` or `Shift` keys.
* `None`—No selection is allowed.

## Selection Units

The DataGrid also provides three selection units, which allow you to manipulate what units are selected when you interact with the grid. To control the selection units, set the `SelectionUnit` property, which accepts the following values:

* (Default) `Row`—Clicking within the cells will select the whole row.
* `Cell`—The clicked cell is selected.

## Selected Items

The DataGrid provides the following properties for getting the data behind the selected items:

* `SelectedItem`—A property of type `object` that gets or sets the currently selected item.

* `SelectedItems`—A property of type `ObservableCollection<object>` that gets an `ObservableCollection` of the currently selected items.

Depending on the `SelectionUnit`, the `SelectedItem` and `SelectedItems` properties will contain different objects. If the `SelectionUnit` is `Cell`, the properties will hold `DataGridCellInfo` objects, which carry information about the selected cell and the underlying data item. If the `SelectionUnit` is `Row`, the properties will hold the business object that represents that row.

## Programmatic Selection

Besides the built-in selection functionality, you can use a programmatic approach to select the data in the DataGrid.

The component exposes the following methods for programmatic selection:

* `SelectItem`(object item)—Selects the provided data item and adds it in the `SelectedItems` collection.
* `DeselectItem`(object item)—Removes the selection for the provided data item and removes it from the `SelectedItems` collection.
* `SelectCell`(`DataGridCellInfo` item)—Selects the grid cell as defined by the provided cell information.
* `DeselectCell`(`DataGridCellInfo` item)—Removes the selection for the grid cell defined by the provided cell information.
* `SelectAll`()—Selects all the items as defined by the `SelectionMode` and `SelectionUnit` properties.
* `DeselectAll`()—Clears the current selected items as defined by the `SelectionUnit` properties.

## Events

The DataGrid exposes the `SelectionChanged` event, which will be raised whenever the selection is changed. The event arguments provide information about the added and removed items.