ObserveOnDispatcher duplicates records

问题

I'm using WPF with Firebase to work with data.

When I use the following code to reveal all data to Datagrid:

void ShowProducts()
{
    var products = client
         .Child("freshfish")
         .AsObservable<Products>();

    ProductsDataGrid.ItemsSource = products
        .ObserveOnDispatcher()
        .AsObservableCollection();
}

It works well, but after a few minutes it duplicates all the records once again.

Here's how it looks:

Any ideas?

来源：https://stackoverflow.com/questions/61240052/observeondispatcher-duplicates-records