How to Populate Child Nodes Asynchronously in UWP TreeGrid?

This example illustrates how to populate child nodes asynchronously in UWP TreeGrid (SfTreeGrid).

You can populate the child nodes asynchronously using async and await at runtime when retrieving data from web services or any database. This can be performed by PopulateChildNodes method from TreeGridRequestTreeItemsEventArgs.ParentNode property.

private async void TreeGrid_RequestTreeItems(object sender, TreeGridRequestTreeItemsEventArgs args)
{
    if (args.ParentItem == null)
    {
        args.ChildItems =  viewModel.Employees.Where(x => x.ReportsTo == -1);
    }
    //if ParentItem not null, then set args.ChildList to the child items for the given ParentItem.
    else
    {
        EmployeeInfo ems = args.ParentItem as EmployeeInfo;
              
        if (ems != null)
        {
            await Task.Run(async () =>
            {
                await this.treeGrid.Dispatcher.RunAsync(CoreDispatcherPriority.High, async() =>
                {
                    //Get the child items with time delay
                    var childItems = await viewModel.GetEmployees(ems.ID);

                    //Populate the child nodes based on the child items
                    args.ParentNode.PopulateChildNodes(childItems);
                });
                       
            });
        }
    }
}