CellMeasurer.md

CellMeasurer

High-order component for automatically measuring a cell's contents by rendering it in a way that is not visible to the user. Specify a fixed width or height constraint if you only want to measure one dimension.

Warning: This HOC is fairly experimental and may change in future releases. At this time it is only intended for use with a Grid (not VirtualScroll or FlexTable as their item rendering and cell measuring signatures are different). Also note that in order to measure a column's width for a Grid, that column's content must be rendered for all rows in order to determine the maximum width. For this reason it may not be a good idea to use this HOC for Grids containing a large number of both columns and cells.

Prop Types

Property	Type	Required?	Description
cellRenderer	Function	✓	Renders a cell given its indices. ({ columnIndex: number, rowIndex: number }): PropTypes.node
children	Function	✓	Function respondible for rendering a virtualized component; ({ getColumnWidth: Function, getRowHeight: Function, resetMeasurements: Function }) => PropTypes.element
columnCount	number	✓	Number of columns in the Grid; in order to measure a row's height, all of that row's columns must be rendered.
container			A Node, Component instance, or function that returns either. If this property is not specified the document body will be used.
height	number		Fixed height; specify this property to measure cell-width only.
rowCount	number	✓	Number of rows in the Grid; in order to measure a column's width, all of that column's rows must be rendered.
width	number		Fixed width; specify this property to measure cell-height only.

Children function

The child function is passed the following named parameters:

Parameter	Type	Description
getColumnWidth	Function	Callback to set as the columnWidth property of a Grid
getRowHeight	Function	Callback to set as the rowHeight property of a Grid
resetMeasurementForColumn(index)	Function	Use this function to clear cached measurements for specific column in CellRenderer; its size will be remeasured the next time it is requested.
resetMeasurementForRow(index)	Function	Use this function to clear cached measurements for specific row in CellRenderer; its size will be remeasured the next time it is requested.
resetMeasurements	Function	Use this function to clear cached measurements in CellRenderer; each cell will be remeasured the next time its size is requested.

Examples

This example shows a Grid with fixed column widths and dynamic row heights. For more examples check out the component demo page.

import React from 'react';
import ReactDOM from 'react-dom';
import { CellMeasurer, Grid } from 'react-virtualized';
import 'react-virtualized/styles.css'; // only needs to be imported once

ReactDOM.render(
  <CellMeasurer
    cellRenderer={cellRenderer}
    columnCount={columnCount}
    height={height}
    rowCount={rowCount}
  >
    {({ getColumnWidth }) => (
      <Grid
        columnCount={columnCount}
        columnWidth={getColumnWidth}
        height={height}
        cellRenderer={cellRenderer}
        rowCount={rowCount}
        rowHeight={fixedRowHeight}
        width={width}
      />
    )}
  </CellMeasurer>,
  document.getElementById('example')
);