- Qt 6.8
- Qt Charts
- QML Types
- VBoxPlotModelMapper
- Qt Charts | Commercial or GPLv3

# VBoxPlotModelMapper QML Type

Vertical model mapper for box plot series. More...

Import Statement: | `import QtCharts 2.8`
In C++: | QVBoxPlotModelMapper

- List of all members, including inherited members

## Properties

- firstBoxSetColumn : int
- firstRow : int
- lastBoxSetColumn : int
- model : SomeModel
- rowCount : int
- series : AbstractBarSeries

## Detailed Description

The VBoxPlotModelMapper type enables using a data model derived from the QAbstractItemModel class as a data source for a chart. A vertical model mapper is used to create a connection between a data model and a BoxPlotSeries type, so that each column in the data model defines a box-and-whiskers item and each row maps to the range and three median values of the box-and-whiskers item.

Both model and series properties can be used to manipulate the data. The model mapper keeps the series and the data model in sync.

The model mapper ensures that all the bar box-and-whiskers items in the box plot series have equal sizes. Therefore, adding or removing a value from a box-and-whiskers item causes the same change to be made in all the box-and-whiskers items in the box plot series.

The following QML code snippet creates a box plot series with three box-and-whiskers items (assuming the model has at least four columns). Each box-and-whiskers item contains data starting from row 1. The name of an item is defined by the column header.

     BoxPlotSeries {
         VBoxPlotModelMapper {
             model: myCustomModel // QAbstractItemModel derived implementation
             firstBoxSetColumn: 1
             lastBoxSetColumn: 3
             firstRow: 1
         }
     }

See also HBoxPlotModelMapper.

## Property Documentation

firstBoxSetColumn : int

The column of the model that is used as the data source for the first box-and-whiskers item. The default value is -1 (invalid mapping).

firstRow : int

The row of the model that contains the first values of the box-and-whiskers items in the box plot series.

The default value is 0.

lastBoxSetColumn : int

The column of the model that is used as the data source for the last box-and-whiskers item. The default value is -1 (invalid mapping).

model : SomeModel

The data model that is used by the mapper. You need to implement the model and expose it to QML.

Note: The model has to support adding and removing rows or columns and modifying the data in the cells.

rowCount : int

The number of rows of the model that are mapped as the data for the box plot series.

The default value is -1 (number limited to the number of columns in the model).

series : AbstractBarSeries

The box plot series that is used by the mapper.

All the data in the series is discarded when it is set to the mapper. When a new series is specified, the old series is disconnected (but it preserves its data).