From fea75a51b9e416a6a4427c9d2c7b56092e6c0091 Mon Sep 17 00:00:00 2001
From: Vladimir Pecanac <vladimir.pecanac@gmail.com>
Date: Wed, 19 Aug 2026 12:46:37 +0200
Subject: [PATCH] Update DifferenceBetweenFieldsAndProperty sample to .NET 10

Retarget both projects from net8.0 to net10.0 and add a RectangleWithFieldKeyword
type that expresses the same width validation with the C# 14 field keyword, next
to the existing hand-written backing-field version so both forms are in the sample.
---
 .../DifferenceBetweenFieldsAndProperty.csproj    |  2 +-
 .../RectangleWithFieldKeyword.cs                 | 14 ++++++++++++++
 .../Tests/Tests.cs                               | 16 ++++++++++++++++
 .../Tests/Tests.csproj                           |  2 +-
 4 files changed, 32 insertions(+), 2 deletions(-)
 create mode 100644 csharp-intermediate-topics/DifferenceBetweenFieldsAndProperty/DifferenceBetweenFieldsAndProperty/RectangleWithFieldKeyword.cs

diff --git a/csharp-intermediate-topics/DifferenceBetweenFieldsAndProperty/DifferenceBetweenFieldsAndProperty/DifferenceBetweenFieldsAndProperty.csproj b/csharp-intermediate-topics/DifferenceBetweenFieldsAndProperty/DifferenceBetweenFieldsAndProperty/DifferenceBetweenFieldsAndProperty.csproj
index 2150e3797b..ed9781c223 100644
--- a/csharp-intermediate-topics/DifferenceBetweenFieldsAndProperty/DifferenceBetweenFieldsAndProperty/DifferenceBetweenFieldsAndProperty.csproj
+++ b/csharp-intermediate-topics/DifferenceBetweenFieldsAndProperty/DifferenceBetweenFieldsAndProperty/DifferenceBetweenFieldsAndProperty.csproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFramework>net10.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
   </PropertyGroup>
diff --git a/csharp-intermediate-topics/DifferenceBetweenFieldsAndProperty/DifferenceBetweenFieldsAndProperty/RectangleWithFieldKeyword.cs b/csharp-intermediate-topics/DifferenceBetweenFieldsAndProperty/DifferenceBetweenFieldsAndProperty/RectangleWithFieldKeyword.cs
new file mode 100644
index 0000000000..87e5581315
--- /dev/null
+++ b/csharp-intermediate-topics/DifferenceBetweenFieldsAndProperty/DifferenceBetweenFieldsAndProperty/RectangleWithFieldKeyword.cs
@@ -0,0 +1,14 @@
+namespace DifferenceBetweenFieldsAndProperty;
+
+// The same validation as Rectangle.Width, written with the C# 14 `field` keyword
+// instead of a hand-declared private backing field.
+public class RectangleWithFieldKeyword
+{
+    public double Width
+    {
+        get;
+        set => field = value >= 0
+            ? value
+            : throw new ArgumentException("A Rectangle can't have negative width", nameof(value));
+    }
+}
diff --git a/csharp-intermediate-topics/DifferenceBetweenFieldsAndProperty/Tests/Tests.cs b/csharp-intermediate-topics/DifferenceBetweenFieldsAndProperty/Tests/Tests.cs
index 9e2c39891f..054b34b8af 100644
--- a/csharp-intermediate-topics/DifferenceBetweenFieldsAndProperty/Tests/Tests.cs
+++ b/csharp-intermediate-topics/DifferenceBetweenFieldsAndProperty/Tests/Tests.cs
@@ -20,4 +20,20 @@ public void GivenRectangle_WhenScaling_ThenReturnsScaledDimensions()
 
         Assert.Equal(105, scaledRectangle.Height);
     }
+
+    [Fact]
+    public void GivenRectangleWithFieldKeyword_WhenAssigningNegativeWidth_ThenThrowsException()
+    {
+        var rectangle = new RectangleWithFieldKeyword();
+
+        Assert.Throws<ArgumentException>(() => rectangle.Width = -2);
+    }
+
+    [Fact]
+    public void GivenRectangleWithFieldKeyword_WhenAssigningValidWidth_ThenStoresValue()
+    {
+        var rectangle = new RectangleWithFieldKeyword { Width = 14 };
+
+        Assert.Equal(14, rectangle.Width);
+    }
 }
\ No newline at end of file
diff --git a/csharp-intermediate-topics/DifferenceBetweenFieldsAndProperty/Tests/Tests.csproj b/csharp-intermediate-topics/DifferenceBetweenFieldsAndProperty/Tests/Tests.csproj
index 3ae64a9baf..2447f831b6 100644
--- a/csharp-intermediate-topics/DifferenceBetweenFieldsAndProperty/Tests/Tests.csproj
+++ b/csharp-intermediate-topics/DifferenceBetweenFieldsAndProperty/Tests/Tests.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFramework>net10.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>