Add code example for CA2224 rule, for C# (#49064)

docs/fundamentals/code-analysis/quality-rules/ca2224.md

@@ -9,6 +9,9 @@ f1_keywords:
 helpviewer_keywords:
   - "OverrideEqualsOnOverloadingOperatorEquals"
   - "CA2224"
+dev_langs:
+- CSharp
+- VB
 ---
 # CA2224: Override Equals on overloading operator equals
 
@@ -62,10 +65,14 @@ For more information, see [How to suppress code analysis warnings](../suppress-w
 
 The following example shows a class (reference type) that violates this rule.
 
+:::code language="csharp" source="snippets/csharp/all-rules/ca2224.cs" id="snippet1":::
+
 :::code language="vb" source="snippets/vb/all-rules/ca2224.vb" id="1":::
 
 The following example fixes the violation by overriding <xref:System.Object.Equals%2A?displayProperty=fullName>.
 
+:::code language="csharp" source="snippets/csharp/all-rules/ca2224.cs" id="snippet2":::
+
 :::code language="vb" source="snippets/vb/all-rules/ca2224.vb" id="2":::
 
 ## Related rules

docs/fundamentals/code-analysis/quality-rules/snippets/csharp/all-rules/ca2224.cs

@@ -0,0 +1,87 @@
+using System;
+
+namespace ca2224
+{
+    //<snippet1>
+    // This class violates the rule.
+    public class Point
+    {
+        public int X { get; set; }
+        public int Y { get; set; }
+
+        public Point(int x, int y)
+        {
+            X = x;
+            Y = y;
+        }
+
+        public override int GetHashCode()
+        {
+            return HashCode.Combine(X, Y);
+        }
+
+        public static bool operator ==(Point pt1, Point pt2)
+        {
+            if (ReferenceEquals(pt1, null) || ReferenceEquals(pt2, null))
+                return false;
+
+            if (pt1.GetType() != pt2.GetType())
+                return false;
+
+            return pt1.X == pt2.X && pt1.Y == pt2.Y;
+        }
+
+        public static bool operator !=(Point pt1, Point pt2)
+        {
+            return !(pt1 == pt2);
+        }
+    }
+    //</snippet1>
+}
+
+namespace ca2224_2
+{
+    //<snippet2>
+    // This class satisfies the rule.
+    public class Point
+    {
+        public int X { get; set; }
+        public int Y { get; set; }
+
+        public Point(int x, int y)
+        {
+            X = x;
+            Y = y;
+        }
+
+        public override int GetHashCode()
+        {
+            return HashCode.Combine(X, Y);
+        }
+
+        public override bool Equals(object? obj)
+        {
+            if (obj is null)
+                return false;
+
+            if (GetType() != obj.GetType())
+                return false;
+
+            Point pt = (Point)obj;
+            return X == pt.X && Y == pt.Y;
+        }
+
+        public static bool operator ==(Point? pt1, Point? pt2)
+        {
+            // Object.Equals calls Point.Equals(Object).
+            return Equals(pt1, pt2);
+        }
+
+        public static bool operator !=(Point? pt1, Point? pt2)
+        {
+            // Object.Equals calls Point.Equals(Object).
+            return !Equals(pt1, pt2);
+        }
+    }
+    //</snippet2>
+}