One of the major data-processing features adopted from the ASPxGridView allows end-users to select multiple list items within a dropdown grid. The selection behavior is controlled by the ASPxGridLookup.SelectionMode property, which can be set to Single (only one item can be selected within the editor) or Multiple (multiple items can be selected within the editor).
In single-selection mode, the GridLookup always synchronizes its value with the focused row in the drop-down grid when a user sorts grid columns, navigates through pages,etc. You can press ESC to rollback a newly selected value and restore an original editor's value.
This functionality is controlled by the ASPxGridLookup.TextFormatString and ASPxGridLookup.MultiTextSeparator properties. The TextFormatString property defines the pattern used to format a selected item's text for display within the editor's edit box. The MultiTextSeparator property specifies a value separator. List items (grid rows) that correspond to the tag names entered are selected automatically once the entered value has been submitted (for instance, by pressing the ENTER key or invoking the dropdown window).
How to Access the Selected Items Programmatically
ASPxGridView behavior varies based on the specified mode.
If the SelectionMode property is set to Single, you should utilize a focused row instead of a selected row. In this case, use the ASPxGridLookup.Value property on the server side and the GetValue/SetValue methods on the client side to get/set the focused row.
If the SelectionMode property is set to Multiple, you can access the selected items' values via the child ASPxGridView control's members.