MemberAdminWindow: Cache MembersDeliveries

Elwig/Windows/MemberAdminWindow.xaml.cs

@@ -187,6 +187,10 @@ namespace Elwig.Windows {
             ControlUtils.RenewItemsSource(BranchInput, await ctx.Branches.OrderBy(b => b.Name).ToListAsync());
             ControlUtils.RenewItemsSource(DefaultKgInput, await ctx.WbKgs.Select(k => k.AtKg).OrderBy(k => k.Name).ToListAsync());
 
+            ViewModel.MembersDeliveries = await ctx.Deliveries
+                .GroupBy(d => new { d.MgNr, d.Year })
+                .ToDictionaryAsync(g => (g.Key.MgNr, g.Key.Year), g => g.Any());
+
             var seasons = await ctx.Seasons.OrderByDescending(s => s.Year).ToListAsync();
             Menu_DeliveryConfirmation.Items.Clear();
             foreach (var s in seasons) {