React 虚拟化自动滚动问题

Question

I am using react-virtualized v-9.21.2 to display a list, I am having an issue on insertion of a new item, upon inserting a new item to the list I am clearing the cache and updating the listkey to auto resize the height, otherwise, the new added item will be cropped but when the listkey get updated the list automatically scroll to top and this is not a desired behavior, my code is as follow:

 UNSAFE_componentWillReceiveProps(nextprops) {
    if (this.props.items.length !== nexprops.items.lenght)) {
    // clear the cache and update the listKey
    this.cache.clearAll();
    this.virtualizedList && this.virtualizedList.recomputeRowHeights();
    this.listKey += 1
 }


renderItem = ({ index, key, parent, style }) => {
        return (
            <CellMeasurer
                cache={this.cache}
                columnIndex={0}
                key={`CellMeasurerRow_${key}`}
                parent={parent}
                rowIndex={index} >
                <div
                    key={`Item__${key}`}
                    style={style}
                    className='row'>
                    <Item
                        style={style}
                        key={`Item_${index}`}
                    />
                </div>
            </CellMeasurer>
        )
    }



render(){
    return (
        <WindowScroller
            key={`Scroller_${this.listKey}`}
            ref={(e) => this.windowRef = e} >
            {({ height, isScrolling, onChildScroll, registerChild, scrollTop, }) => (
                <AutoSizer>
                    {({ width }) => (
                        <React.Fragment key={registerChild}>
                            <List
                                ref={`ListKey_${this.listKey}`}
                                autoHeight
                                isScrolling={isScrolling}
                                onScroll={onChildScroll}
                                key={this.listKey}
                                scrollTop={scrollTop}
                                height={height}
                                rowCount={this.props.items.length}
                                rowRenderer={this.renderItem}
                                deferredMeasurementCache={this.cache}
                                rowHeight={this.cache.rowHeight}
                                width={width}
                                overscanRowCount={10} />
                     

                        </React.Fragment>
                    )}
                </AutoSizer>
            )}
        </WindowScroller>
    )
}

I tried programmatically to scroll to adjust the height without the update of the key, it worked but still not accurate, So, How can I update the virtualized with a new item and adjust the height without scrolling??

Answer 1

If your data has a unique key, I think you can create a ListItem component add an useEffect hook calling the measure function when the data change. This may have performance impact.

function ListItem(props) {
  useEffect(props.measure, [props.data.id]);
  return (
    <div style={props.style}>
      {/* content render */}
    </div>
  );
}

renderItem = ({ index, key, parent, style }) => {
        const item = getItem(index); // suppose item data structure: { id: unique_key }
        return (
            <CellMeasurer
                cache={this.cache}
                columnIndex={0}
                key={`CellMeasurerRow_${key}`}
                parent={parent}
                rowIndex={index} 
            >
               {(measure) => (
                  <ListItem 
                    key={`Item__${key}`} style={style} 
                    data={item}
                    measure={measure}
                  />
               )}
            </CellMeasurer>
        )
    }