From bfb795c8ed370eb814da2b8f1b626c1fef6f0f86 Mon Sep 17 00:00:00 2001
From: Vladimir Pecanac <vladimir.pecanac@gmail.com>
Date: Wed, 19 Aug 2026 12:46:41 +0200
Subject: [PATCH] Update IEnumerable vs ICollection vs IList vs List sample to
 .NET 10

Retarget both projects from net7.0 to net10.0 and add a deferred-execution
demonstration showing that a LINQ query re-runs on every enumeration while a
materialised ICollection<T> just reads a stored count.
---
 .../DeferredExecutionDemo.cs                    | 17 +++++++++++++++++
 ...IEnumerableVsICollectionVsIListVsList.csproj |  2 +-
 .../Program.cs                                  |  5 +++++
 .../Tests/Tests.csproj                          |  2 +-
 4 files changed, 24 insertions(+), 2 deletions(-)
 create mode 100644 collections-csharp/IEnumerableVsICollectionVsIListVsList/IEnumerableVsICollectionVsIListVsList/DeferredExecutionDemo.cs

diff --git a/collections-csharp/IEnumerableVsICollectionVsIListVsList/IEnumerableVsICollectionVsIListVsList/DeferredExecutionDemo.cs b/collections-csharp/IEnumerableVsICollectionVsIListVsList/IEnumerableVsICollectionVsIListVsList/DeferredExecutionDemo.cs
new file mode 100644
index 0000000000..0b97db41a6
--- /dev/null
+++ b/collections-csharp/IEnumerableVsICollectionVsIListVsList/IEnumerableVsICollectionVsIListVsList/DeferredExecutionDemo.cs
@@ -0,0 +1,17 @@
+namespace IEnumerableVsICollectionVsIListVsList
+{
+    public class DeferredExecutionDemo
+    {
+        public void ShowDeferredVsMaterialised(IEnumerable<int> numbers)
+        {
+            IEnumerable<int> query = numbers.Where(n => n > 10);
+
+            Console.WriteLine(query.Count());   // runs the filter
+            Console.WriteLine(query.Count());   // runs the filter again
+
+            ICollection<int> materialised = query.ToList();
+
+            Console.WriteLine(materialised.Count);   // reads a stored value
+        }
+    }
+}
diff --git a/collections-csharp/IEnumerableVsICollectionVsIListVsList/IEnumerableVsICollectionVsIListVsList/IEnumerableVsICollectionVsIListVsList.csproj b/collections-csharp/IEnumerableVsICollectionVsIListVsList/IEnumerableVsICollectionVsIListVsList/IEnumerableVsICollectionVsIListVsList.csproj
index f02677bf64..dfb40caafc 100644
--- a/collections-csharp/IEnumerableVsICollectionVsIListVsList/IEnumerableVsICollectionVsIListVsList/IEnumerableVsICollectionVsIListVsList.csproj
+++ b/collections-csharp/IEnumerableVsICollectionVsIListVsList/IEnumerableVsICollectionVsIListVsList/IEnumerableVsICollectionVsIListVsList.csproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>net7.0</TargetFramework>
+    <TargetFramework>net10.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
   </PropertyGroup>
diff --git a/collections-csharp/IEnumerableVsICollectionVsIListVsList/IEnumerableVsICollectionVsIListVsList/Program.cs b/collections-csharp/IEnumerableVsICollectionVsIListVsList/IEnumerableVsICollectionVsIListVsList/Program.cs
index fd8b07c512..6c7cd01aa3 100644
--- a/collections-csharp/IEnumerableVsICollectionVsIListVsList/IEnumerableVsICollectionVsIListVsList/Program.cs
+++ b/collections-csharp/IEnumerableVsICollectionVsIListVsList/IEnumerableVsICollectionVsIListVsList/Program.cs
@@ -36,6 +36,11 @@ static void Main(string[] args)
             output = lst.CountSpecialCharacters(specialCharacter);
             Console.WriteLine($"List:{output}");
 
+            //Deferred execution vs a materialised collection
+            var deferred = new DeferredExecutionDemo();
+            Console.WriteLine($"Deferred vs materialised:");
+            deferred.ShowDeferredVsMaterialised(new List<int> { 5, 11, 12, 42 });
+
             Console.ReadLine();
         }       
     }    
diff --git a/collections-csharp/IEnumerableVsICollectionVsIListVsList/Tests/Tests.csproj b/collections-csharp/IEnumerableVsICollectionVsIListVsList/Tests/Tests.csproj
index c454e67014..f93e17bc1e 100644
--- a/collections-csharp/IEnumerableVsICollectionVsIListVsList/Tests/Tests.csproj
+++ b/collections-csharp/IEnumerableVsICollectionVsIListVsList/Tests/Tests.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net7.0</TargetFramework>
+    <TargetFramework>net10.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>