React Hierarchical Grid Remote Data Operations

By default, the IgrHierarchicalGrid uses its own logic for performing data operations.

You can perform these tasks remotely and feed the resulting data to the IgrHierarchicalGrid by taking advantage of certain inputs and events, which are exposed by the IgrHierarchicalGrid.

Infinite Scroll

A popular design for scenarios requiring fetching data by chunks from an end-point is the so-called infinite scroll. For data grids, it is characterized by continuous increase of the loaded data triggered by the end-user scrolling all the way to the bottom. The next paragraphs explain how you can use the available API to easily achieve infinite scrolling in IgrHierarchicalGrid.

To implement infinite scroll, you have to fetch the data in chunks. The data that is already fetched should be stored locally and you have to determine the length of a chunk and how many chunks there are. You also have to keep a track of the last visible data row index in the grid. In this way, using the IgrForOfState.chunkSize and IgrForOfState.chunkSize properties, you can determine if the user scrolls up and you have to show them already fetched data or scrolls down and you have to fetch more data from the end-point.

The first thing to do is fetch the first chunk of the data. Setting the IgrHierarchicalGrid.totalItemCount property is important, as it allows the grid to size its scrollbar correctly.

Additionally, you have to subscribe to the IgrIgrHierarchicalGrid.dataPreLoad output, so that you can provide the data needed by the grid when it tries to display a different chunk, rather than the currently loaded one. In the event handler, you have to determine whether to fetch new data or return data, that’s already cached locally.

Infinite Scroll Demo

Remote Paging

const BASE_URL = `https://data-northwind.indigo.design/`;
const CUSTOMERS_URL = `${BASE_URL}Customers/GetCustomersWithPage`;

export class RemoteService {

    public static getCustomersDataWithPaging(pageIndex?: number, pageSize?: number) {
        return fetch(this.buildUrl(CUSTOMERS_URL, pageIndex, pageSize))
        .then((result) => result.json());
    }

    public static getHierarchyDataById(parentEntityName: string, parentId: string, childEntityName: string) {
        return fetch(`${BASE_URL}${parentEntityName}/${parentId}/${childEntityName}`)
        .then((result) => result.json());
    }

    private static buildUrl(baseUrl: string, pageIndex?: number, pageSize?: number) {
        let qS = "";
        if (baseUrl) {
                qS += `${baseUrl}`;
        }

        // Add pageIndex and size to the query string if they are defined
        if (pageIndex !== undefined) {
            qS += `?pageIndex=${pageIndex}`;
            if (pageSize !== undefined) {
                qS += `&size=${pageSize}`;
            }
        } else if (pageSize !== undefined) {
            qS += `?perPage=${pageSize}`;
        }

        return `${qS}`;
    }
}

After declaring the service, we need to create a component, which will be responsible for the IgrHierarchicalGrid construction and data subscription.

  <IgrHierarchicalGrid
          ref={hierarchicalGrid}
          data={data}
          pagingMode="remote"
          primaryKey="customerId"
          height="600px"
        >
          <IgrPaginator
            perPage={perPage}
            ref={paginator}
            onPageChange={onPageNumberChange}
            onPerPageChange={onPageSizeChange}
          ></IgrPaginator>
          ...
          <IgrRowIsland
            childDataKey="Orders"
            primaryKey="orderId"
            onGridCreated={onCustomersGridCreatedHandler}>
            ...

            <IgrRowIsland
              childDataKey="Details"
              primaryKey="productId"
              onGridCreated={onOrdersGridCreatedHandler}>
              ...
            </IgrRowIsland>
          </IgrRowIsland>
        </IgrHierarchicalGrid>

then set up the state:

  const hierarchicalGrid = useRef<IgrHierarchicalGrid>(null);
  const paginator = useRef<IgrPaginator>(null);

  const [data, setData] = useState([]);
  const [page, setPage] = useState(0);
  const [perPage, setPerPage] = useState(15);
  const [isLoading, setIsLoading] = useState(true);

  useEffect(() => {
    loadGridData(page, perPage);
  }, [page, perPage]);

next set up the method for loading the data:

  function loadGridData(pageIndex?: number, pageSize?: number) {
    // Set loading state
    setIsLoading(true);

    // Fetch data
    RemoteService.getCustomersDataWithPaging(pageIndex, pageSize)
      .then((response: CustomersWithPageResponseModel) => {
        setData(response.items);
        // Stop loading when data is retrieved
        setIsLoading(false);
        paginator.current.totalRecords = response.totalRecordsCount;
      })
      .catch((error) => {
        console.error(error.message);
        setData([]);
        // Stop loading even if error occurs. Prevents endless loading
        setIsLoading(false);
      })
  }

and finally set up the behaviour for the RowIslands:

  function gridCreated(event: IgrGridCreatedEventArgs, parentKey: string) {
    const context = event.detail;
    context.grid.isLoading = true;

    const parentId: string = context.parentID;
    const childDataKey: string = context.owner.childDataKey;

    RemoteService.getHierarchyDataById(parentKey, parentId, childDataKey)
      .then((data: any) => {
        context.grid.data = data;
        context.grid.isLoading = false;
        context.grid.markForCheck();
      })
      .catch((error) => {
        console.error(error.message);
        context.grid.data = [];
        context.grid.isLoading = false;
        context.grid.markForCheck();
      });
  }

  const onCustomersGridCreatedHandler = (e: IgrGridCreatedEventArgs) => {
    gridCreated(e, "Customers")
  };

  const onOrdersGridCreatedHandler = (e: IgrGridCreatedEventArgs) => {
    gridCreated(e, "Orders")
  };

For further reference please check the full sample bellow:

Grid Remote Paging Demo

Known Issues and Limitations

• When the grid has no IgrHierarchicalGrid.primaryKey set and remote data scenarios are enabled (when paging, sorting, filtering, scrolling trigger requests to a remote server to retrieve the data to be displayed in the grid), a row will lose the following state after a data request completes:

• Row Selection

• Row Expand/collapse

• Row Editing

• Row Pinning

API References

Additional Resources

Our community is active and always welcoming to new ideas.

• Ignite UI for React Forums
• Ignite UI for React GitHub