If you're using Blazor WebAssembly, it's very common to fetch data from a JSON API on a server. If you want to fetch only the data that's needed for the current page/viewport and apply any sorting or filtering rules on the server, you can use the ItemsProvider parameter.

You can also use ItemsProvider with Blazor Server if it needs to query an external endpoint, or in any other case where your requirements aren't covered by an IQueryable.

To do this, supply a callback matching the GridItemsProvider<TGridItem> delegate type, where TGridItem is the type of data displayed in the grid. Your callback will be given a parameter of type GridItemsProviderRequest<TGridItem> which specifies the start index, maximum row count, and sort order of data to return. As well as returning the matching items, you need to return a totalItemCount so that paging or virtualization can work.

Here is an example of connecting a grid to the public OpenFDA Food Enforcement database.

This grid is using a 'sticky' header (i.e. the header is always visible when scrolling). The buttons in the last column disappear under the header when scrolling. In this example they don't really do anything more than writing a message in the console log'

The second column has a custom Style parameter set and applied to it. The 4th column has its Tooltip parameter set to true. This will show the full content of the cell when hovering over it. See the 'Razor' tab for how these parameters have been applied.

If the external endpoint controls filtering, paging and sorting you can use Items combined with RefreshItems.

The method defined in RefreshItems will be called once, and only once, if there is a change in the pagination or ordering.

Meanwhile, you can control the filtering with elements present on the page itself and force a call to RefreshItems with the force option in the RefreshDataAsync.