diff --git a/src/Mobile/eShopOnContainers/eShopOnContainers.Core/ViewModels/CatalogViewModel.cs b/src/Mobile/eShopOnContainers/eShopOnContainers.Core/ViewModels/CatalogViewModel.cs
index 1554f7fb0..215f99098 100644
--- a/src/Mobile/eShopOnContainers/eShopOnContainers.Core/ViewModels/CatalogViewModel.cs
+++ b/src/Mobile/eShopOnContainers/eShopOnContainers.Core/ViewModels/CatalogViewModel.cs
@@ -15,7 +15,7 @@ namespace eShopOnContainers.Core.ViewModels
         private CatalogBrand _brand;
         private ObservableCollection<CatalogType> _types;
         private CatalogType _type;
-        private ICatalogService _productsService;
+        private readonly ICatalogService _productsService;
 
         public CatalogViewModel(ICatalogService productsService)
         {
@@ -127,4 +127,4 @@ namespace eShopOnContainers.Core.ViewModels
             IsBusy = false;
         }
     }
-}
\ No newline at end of file
+}