The Columns property can vary the number of vertical or horizontal columns, depending on the value of Directionality. The full path to this property is Legend.Columns. The following image shows a sample legend with markers split into two horizontal columns (Direction property set to Top to Bottom).

If you set the column property to 2, and set the property direction from left to right, then the markers are split into two vertical columns. The following image shows a sample legend with markers split into two vertical columns (Direction property set to Left to Right).

of the columnA property can have one of the following values. You must set this property. It cannot be left empty.