New Breadcrumb user control

New Breadcrumb service
WIP icons and back button behavior

WinAppCommon/ViewModels/UserControls/BreadcrumbControlVm.cs

@@ -0,0 +1,45 @@
+using System.Collections.Generic;
+using System.Linq;
+using GalaSoft.MvvmLight.Command;
+using GalaSoft.MvvmLight.Views;
+using ModernKeePass.Application.Common.Interfaces;
+using ModernKeePass.Application.Common.Models;
+using ModernKeePass.Common;
+using ModernKeePass.Models;
+
+namespace ModernKeePass.ViewModels
+{
+    public class BreadcrumbControlVm
+    {
+        public IEnumerable<BreadcrumbItem> BreadcrumbItems { get; }
+        public string ParentGroupName => BreadcrumbItems.Last()?.Name;
+
+        public RelayCommand GoBackCommand { get; }
+        public RelayCommand<int> GoToCommand { get; }
+
+        private readonly INavigationService _navigation;
+        private readonly IBreadcrumbService _breadcrumb;
+
+        public BreadcrumbControlVm(INavigationService navigation, IBreadcrumbService breadcrumb)
+        {
+            _navigation = navigation;
+            _breadcrumb = breadcrumb;
+
+            BreadcrumbItems = _breadcrumb.GetItems().Reverse();
+            GoBackCommand = new RelayCommand(GoBack);
+            GoToCommand = new RelayCommand<int>(GoTo);
+        }
+
+        private void GoTo(int index)
+        {
+            var breadcrumb = _breadcrumb.Pop(BreadcrumbItems.Count() - index);
+            _navigation.NavigateTo(Constants.Navigation.GroupPage, new NavigationItem { Id = breadcrumb.Path });
+        }
+
+        private void GoBack()
+        {
+            _breadcrumb.Pop();
+            _navigation.GoBack();
+        }
+    }
+}