Improve Lifetimes example in chapter 10 (to show previous values)

Author: andrewlock

Chapter10/D_LifetimeExamples/LifetimeExamples/Pages/RowCount/Captured.cshtml.cs

@@ -11,6 +11,7 @@ namespace LifetimeExamples.Pages
 {
     public class CapturedModel : PageModel
     {
+        private readonly static List<RowCountViewModel.Count> _previousCounts = new(); // c#9 feature - target typing
         public RowCountViewModel RowCounts { get; set; }
 
         private readonly CapturingRepository _capturingRepo;
@@ -27,10 +28,16 @@ ScopedDataContext scopedDataContext
 
         public void OnGet()
         {
+            var count = new RowCountViewModel.Count
+            {
+                DataContext = _scopedDataContext.RowCount,
+                Repository = _capturingRepo.RowCount,
+            };
+            _previousCounts.Insert(0, count);
             RowCounts = new RowCountViewModel
             {
-                DataContextCount = _scopedDataContext.RowCount,
-                RepositoryCount = _capturingRepo.RowCount,
+                Current = count,
+                Previous = _previousCounts,
             };
         }
     }

Chapter10/D_LifetimeExamples/LifetimeExamples/Pages/RowCount/Scoped.cshtml.cs

@@ -11,6 +11,7 @@ namespace LifetimeExamples.Pages
 {
     public class ScopedModel : PageModel
     {
+        private readonly static List<RowCountViewModel.Count> _previousCounts = new(); // c#9 feature - target typing
         public RowCountViewModel RowCounts { get; set; }
 
         private readonly ScopedRepository _scopedRepo;
@@ -27,10 +28,16 @@ ScopedDataContext scopedDataContext
 
         public void OnGet()
         {
+            var count = new RowCountViewModel.Count
+            {
+                DataContext = _scopedDataContext.RowCount,
+                Repository = _scopedRepo.RowCount,
+            };
+            _previousCounts.Insert(0, count);
             RowCounts = new RowCountViewModel
             {
-                DataContextCount = _scopedDataContext.RowCount,
-                RepositoryCount = _scopedRepo.RowCount,
+                Current = count,
+                Previous = _previousCounts,
             };
         }
     }

Chapter10/D_LifetimeExamples/LifetimeExamples/Pages/RowCount/Singleton.cshtml.cs

@@ -11,6 +11,7 @@ namespace LifetimeExamples.Pages
 {
     public class SingletonModel : PageModel
     {
+        private readonly static List<RowCountViewModel.Count> _previousCounts = new(); // c#9 feature - target typing
         public RowCountViewModel RowCounts { get; set; }
 
         private readonly SingletonRepository _singletonRepo;
@@ -27,10 +28,16 @@ SingletonDataContext singletonDataContext
 
         public void OnGet()
         {
+            var count = new RowCountViewModel.Count
+            {
+                DataContext = _singletonDataContext.RowCount,
+                Repository = _singletonRepo.RowCount,
+            };
+            _previousCounts.Insert(0, count);
             RowCounts = new RowCountViewModel
             {
-                DataContextCount = _singletonDataContext.RowCount,
-                RepositoryCount = _singletonRepo.RowCount,
+                Current = count,
+                Previous = _previousCounts,
             };
         }
     }

Chapter10/D_LifetimeExamples/LifetimeExamples/Pages/RowCount/Transient.cshtml.cs

@@ -11,6 +11,7 @@ namespace LifetimeExamples.Pages
 {
     public class TransientModel : PageModel
     {
+        private readonly static List<RowCountViewModel.Count> _previousCounts = new(); // c#9 feature - target typing
         public RowCountViewModel RowCounts { get; set; }
 
         private readonly TransientRepository _transientRepo;
@@ -27,10 +28,16 @@ TransientDataContext transientDataContext
 
         public void OnGet()
         {
+            var count = new RowCountViewModel.Count
+            {
+                DataContext = _transientDataContext.RowCount,
+                Repository = _transientRepo.RowCount,
+            };
+            _previousCounts.Insert(0, count);
             RowCounts = new RowCountViewModel
             {
-                DataContextCount = _transientDataContext.RowCount,
-                RepositoryCount = _transientRepo.RowCount,
+                Current = count,
+                Previous = _previousCounts,
             };
         }
     }

Chapter10/D_LifetimeExamples/LifetimeExamples/Pages/Shared/_RowCounts.cshtml

@@ -1,9 +1,40 @@
 @model RowCountViewModel
 
 <h4>Random row count values</h4>
-<dl class="dl-horizontal">
-    <dt>The <code>DatabaseContext.RowCount</code> is</dt>
-    <dd>@Model.DataContextCount.ToString("###,###,###")</dd>
-    <dt>The <code>Repository.RowCount</code> is</dt>
-    <dd>@Model.RepositoryCount.ToString("###,###,###")</dd>
-</dl>
+
+<dl class="row">
+    <div class="col">
+        <dt>The <em>Current</em> <code>DatabaseContext.RowCount</code> is</dt>
+        <dd>@Model.Current.DataContext.ToString("###,###,###")</dd>
+    </div>
+    <div class="col">
+        <dt>The <em>Current</em> <code>Repository.RowCount</code> is</dt>
+        <dd>@Model.Current.Repository.ToString("###,###,###")</dd>
+    </div>
+</dl>
+
+<h4>Previous values:</h4>
+@if (Model.Previous?.Count > 1)
+{
+    @*Not ideal as itterates list twice, could be refactored*@
+    <dl class="row">
+        <div class="col">
+            <dt>The <em>Previous</em> <code>DatabaseContext.RowCount</code>s are</dt>
+            @foreach (var counts in Model.Previous.Skip(1))
+            {
+                <dd class="col">@counts.DataContext.ToString("###,###,###")</dd>
+            }
+        </div>
+        <div class="col">
+            <dt>The <em>Previous</em> <code>Repository.RowCount</code>s are</dt>
+            @foreach (var counts in Model.Previous.Skip(1))
+            {
+                <dd class="col">@counts.Repository.ToString("###,###,###")</dd>
+            }
+        </div>
+    </dl>
+}
+else
+{
+    <p><em>Hit refresh to generate new random values. Previous values will be listed here</em></p>
+}

Chapter10/D_LifetimeExamples/LifetimeExamples/RowCountViewModel.cs

@@ -1,8 +1,16 @@
-namespace LifetimeExamples
+using System.Collections.Generic;
+
+namespace LifetimeExamples
 {
     public class RowCountViewModel
     {
-        public int DataContextCount { get; set; }
-        public int RepositoryCount { get; set; }
+        public Count Current { get; set; }
+        public List<Count> Previous { get; set; }
+
+        public class Count
+        {
+            public int DataContext { get; set; }
+            public int Repository { get; set; }
+        }
     }
 }