How to Hide the DetailsView Expander Icon Based on Child Records Count in WPF / UWP DataGrid?

This example illustrates how to hide the detailsview expander icon based on child records count in WPF DataGrid and UWP DataGrid (SfDataGrid).

By default, the state of expander icon is visible for all the data rows in parent DataGrid even if its RelationalColumn property has an empty collection or null.

You can customize hiding the details view expander icon by handling the SfDataGrid.QueryDetailsViewExpanderState event. This event occurs when expander icon is changed on expanding or collapsing the details view. You can hide the expander icon by setting the ExpanderVisibility property to false in the SfDataGrid.QueryDetailsViewExpanderState event based on condition.

this.dataGrid.QueryDetailsViewExpanderState += DataGrid_QueryDetailsViewExpanderState;

private void DataGrid_QueryDetailsViewExpanderState(object sender, Syncfusion.UI.Xaml.Grid.QueryDetailsViewExpanderStateEventArgs e)
{
    var orderInfo = e.Record as OrderInfo;
    if (orderInfo != null)
    {
        if (orderInfo.OrderDetails.Count == 0)
        {
            e.ExpanderVisibility = false;
        }
    }
}

The following screenshot illustrates how to hide the state of expander icon based on child items count.

WPF DataGrid Image:

UWP DataGrid Image: