RadDropDownList supports three types of selection modes:
One: Only one item can be selected.
MultiSimple: Multiple items can be selected.
MultiExtended: Multiple selection which can also be performed by using the Ctrl, Shift and arrow keys.
Setting a Selection Mode
this.radDropDownList1.DropDownListElement.SelectionMode = SelectionMode.MultiExtended;
Me.radDropDownList1.DropDownListElement.SelectionMode = SelectionMode.MultiExtended
Select Next Item
RadDropDownList can automatically select the next item when a double click in the edit box is performed.
Next Item Selection
this.radDropDownList1.SelectNextOnDoubleClick = true;
Me.radDropDownList1.SelectNextOnDoubleClick = True
There are couple of events to which you can subscribe your RadDropDownList and retrieve information about the selected value or index:
SelectedIndexChanging: Raised before the index actually changes, the handler is a suitable place to cancel the operation if the application logic requires it.
SelectedIndexChanged: Raised after the index had been changed, the event arguments provide information about the new position of the selected item.
SelectedValueChanged: Raised if RadDropDownList.SelectedValue has been changed.
Programmatically Select Items
Items can be programmatically selected either by their value or by their logical representation, the RadListDataItem. The responsible properties can be directly accessed from the RadDropDownList object:
SelectedValue: Defines the currently selected value, its type needs to be the same as the type of the elements which populate the RadDropDownList.
SelectedItem: This is the logical representation of the selected value, its type is RadListDataItem.
SelectedIndex: Selects an item according to its index in the Items collection.
SelectedItems: Returns a collection of the currently selected items
Setting these properties will result in raising the selection events.
this.radDropDownList1.SelectedItem = this.radDropDownList1.Items;
Me.radDropDownList1.SelectedItem = Me.radDropDownList1.Items(1)