Добавил страницу с подробным описанием телефона.

#1

PhoneStore/Controllers/PhonesController.cs

@@ -137,12 +137,12 @@ namespace PhoneStore.Controllers
         }
 
         [HttpGet]
-        public IActionResult About(int? id)
+        public IActionResult About(int? phoneId)
         {
-            if (!id.HasValue) return RedirectToAction("Error", "Errors", new {statusCode = 777});
+            if (!phoneId.HasValue) return RedirectToAction("Error", "Errors", new {statusCode = 777});
             var phone = _db.Phones
                 .Include(p => p.Brand)
-                .FirstOrDefault(p => p.Id == id);
+                .FirstOrDefault(p => p.Id == phoneId);
             if (phone is null)
                 return RedirectToAction("Error", "Errors", new {statusCode = 777});
             

PhoneStore/Views/Phones/About.cshtml

@@ -6,3 +6,10 @@
 }
 
 <h2>@Model.Name</h2>
+<div class="card mb-3">
+    <img class="card-img-top w-50" src="~/@Model.Image" alt="Card image cap">
+    <div class="card-body">
+        <h5 class="card-title">@Model.Brand.Name</h5>
+        <p class="card-text">@(Model.Price.ToString("C2"))</p>
+    </div>
+</div>
\ No newline at end of file

PhoneStore/Views/Phones/Index.cshtml

@@ -65,6 +65,12 @@ else
                              class="dropdown-item">
                               Изменить
                           </a>
+                          <a asp-route-phoneId="@phone.Id"
+                             asp-action="About"
+                             asp-controller="Phones"
+                             class="dropdown-item">
+                              Подробнее
+                          </a>
                           <a asp-route-phoneId="@phone.Id"
                              asp-action="Delete"
                              asp-controller="Phones"

PhoneStore/Views/Shared/_Layout.cshtml

@@ -35,7 +35,7 @@
                     <p>@User.Identity.Name</p>
                            
                     <form method="post" asp-controller="Account" asp-action="LogOff">
-                        <input type="submit" value="Выход" />
+                        <button class="btn btn-outline-warning" type="submit">Выход</button>
                     </form>
                 }
                 else