Add example for optional attr (#9355)

* Add example for optional attr * Fix up space issues Co-authored-by: Genevieve Warren <[email protected]>
dotnet · Oct 23, 2023 · 05d4f99 · 05d4f99
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diff --git a/snippets/csharp/System.Runtime.InteropServices/OptionalAttribute/Overview/Project.csproj b/snippets/csharp/System.Runtime.InteropServices/OptionalAttribute/Overview/Project.csproj
@@ -0,0 +1,8 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Library</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+  </PropertyGroup>
+
+</Project>
diff --git a/snippets/csharp/System.Runtime.InteropServices/OptionalAttribute/Overview/sample.cs b/snippets/csharp/System.Runtime.InteropServices/OptionalAttribute/Overview/sample.cs
@@ -0,0 +1,18 @@
+//<snippet1>
+using System;
+using System.Runtime.InteropServices;
+
+public class Program
+{
+    public static void MethodWithOptionalAttribute([Optional] string str)
+    {
+        Console.WriteLine($"str is null: {str == null}");
+    }
+
+    public static void Main()
+    {
+        MethodWithOptionalAttribute(); // str is null: True
+        MethodWithOptionalAttribute("abc"); // str is null: False
+    }
+}
+//</snippet1>
diff --git a/xml/System.Runtime.InteropServices/OptionalAttribute.xml b/xml/System.Runtime.InteropServices/OptionalAttribute.xml
@@ -62,6 +62,13 @@
  You can apply this attribute to parameters.  
   
  Optional parameters are not supported by all languages.  
+
+<xref:System.Runtime.InteropServices.OptionalAttribute> is sometimes used in conjunction with <xref:System.Runtime.InteropServices.DefaultParameterValueAttribute>.
+## Examples
+
+The following code example demonstrates how to apply the <xref:System.Runtime.InteropServices.OptionalAttribute> attribute to a parameter of a method written in C#.
+  
+:::code language="csharp" source="~/snippets/csharp/System.Runtime.InteropServices/OptionalAttribute/Overview/sample.cs" id="Snippet1":::
   
  ]]></format>
     </remarks>