Once the FlexPivotSlicer control is bound to a field, which needs to be filtered, it displays all the unique values of that field in a list. You can then simply select the field values from that list, to filter the FlexPivotGrid/FlexPivot Chart data accordingly. By default, the user is allowed to select only one value from the list of field values. However, to allow users to select multiple values in the list, you can make use of the MultiSelect property of the C1FlexPivotSlicer class. When the MultiSelect property is set to true programmatically, multiple items can be selected. You can also use the Multi-Select button shown in the control’s header to change the selection mode for the list at runtime. Toggling the Multi-Select button toggles the value of the MultiSelect property.

'Allows users to select multiple items from the list
c1FlexPivotSlicer.MultiSelect = True

//Allows users to select multiple items from the list
c1FlexPivotSlicer.MultiSelect =true;

When multiple selection is enabled in the list or when the MultiSelect property of the C1FlexPivotSlicer is set to true, the FlexPivotSlicer control shows a Select All/Unselect All checkbox at the top of the list. This checkbox allows you to select/unselect all items of the list in one go. You can choose to display or hide the Select All/Unselect All checkbox using the ShowSelectAll property of the C1FlexPivotSlicer class.

'Displays the Select All checkbox at the top of the list
c1FlexPivotSlicer.ShowSelectAll = True

//Displays the Select All checkbox at the top of the list
c1FlexPivotSlicer.ShowSelectAll = true;

By default, checkboxes are not shown next to the items of the list. However, you can customize the FlexPivotSlicer control to show or hide checkboxes next to each item in the list using the ShowCheckBoxes property of the C1FlexPivotSlicer class.

'Displays checkboxes next to each item in the list
c1FlexPivotSlicer.ShowCheckBoxes = True

//Displays checkboxes next to each item in the list
c1FlexPivotSlicer.ShowCheckBoxes = true;