Add documentation for CustomAttrbute

snippets/csharp/System.Reflection.Metadata/CustomAttribute/Overview/CustomAttributeSnippets.cs

@@ -0,0 +1,63 @@
+using System;
+using System.IO;
+using System.Reflection.Metadata;
+using System.Reflection.PortableExecutable;
+
+static class CustomAttributeSnippets
+{
+    // <SnippetPrintAttributes>
+    static void PrintCustomAttributes(MetadataReader mr, TypeDefinition t)
+    {
+        // Enumerate custom attributes on the type definition
+        foreach (CustomAttributeHandle attrHandle in t.GetCustomAttributes())
+        {
+            CustomAttribute attr = mr.GetCustomAttribute(attrHandle);
+
+            // Display the attribute type full name
+            if (attr.Constructor.Kind == HandleKind.MethodDefinition)
+            {
+                MethodDefinition mdef = mr.GetMethodDefinition((MethodDefinitionHandle)attr.Constructor);
+                TypeDefinition tdef = mr.GetTypeDefinition(mdef.GetDeclaringType());
+                Console.WriteLine($"Type:  {mr.GetString(tdef.Namespace)}.{mr.GetString(tdef.Name)}");
+            }
+            else if (attr.Constructor.Kind == HandleKind.MemberReference)
+            {
+                MemberReference mref = mr.GetMemberReference((MemberReferenceHandle)attr.Constructor);
+
+                if (mref.Parent.Kind == HandleKind.TypeReference)
+                {
+                    TypeReference tref = mr.GetTypeReference((TypeReferenceHandle)mref.Parent);
+                    Console.WriteLine($"Type:  {mr.GetString(tref.Namespace)}.{mr.GetString(tref.Name)}");
+                }
+                else if (mref.Parent.Kind == HandleKind.TypeDefinition)
+                {
+                    TypeDefinition tdef = mr.GetTypeDefinition((TypeDefinitionHandle)mref.Parent);
+                    Console.WriteLine($"Type:  {mr.GetString(tdef.Namespace)}.{mr.GetString(tdef.Name)}");
+                }
+            }
+
+            // Display the attribute value
+            byte[] data = mr.GetBlobBytes(attr.Value);
+            Console.Write("Value: ");
+
+            for (int i = 0; i < data.Length; i++) Console.Write($"{data[i]:X2} ");
+
+            Console.WriteLine();
+        }
+    }
+    // </SnippetPrintAttributes>
+
+    public static void Run()
+    {
+        using var fs = new FileStream(typeof(Program).Assembly.Location, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
+        using var peReader = new PEReader(fs);
+        MetadataReader mr = peReader.GetMetadataReader();
+
+        foreach(TypeDefinitionHandle tdh in mr.TypeDefinitions)
+        {
+            TypeDefinition t = mr.GetTypeDefinition(tdh);
+            Console.WriteLine($"{mr.GetString(t.Namespace)}.{mr.GetString(t.Name)}");
+            PrintCustomAttributes(mr, t);
+        }
+    }
+}

snippets/csharp/System.Reflection.Metadata/CustomAttribute/Overview/CustomAttributeSnippets.csproj

@@ -0,0 +1,9 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

snippets/csharp/System.Reflection.Metadata/CustomAttribute/Overview/Program.cs

@@ -0,0 +1,9 @@
+using System;
+
+class Program
+{
+    static void Main()
+    {
+        CustomAttributeSnippets.Run();        
+    }
+}

xml/System.Reflection.Metadata/CustomAttribute.xml

@@ -31,8 +31,20 @@
     </Attribute>
   </Attributes>
   <Docs>
-    <summary>To be added.</summary>
-    <remarks>To be added.</remarks>
+    <summary>Provides information about a custom attribute.</summary>
+    <remarks>
+      <format type="text/markdown"><![CDATA[
+
+## Remarks
+A custom attribute is an annotation that associates additional information with a metadata element, such as an assembly, type, or method. You can use the <xref:System.Reflection.Metadata.MetadataReader.GetCustomAttribute(System.Reflection.Metadata.CustomAttributeHandle)> method to get a custom attribute instance. For more information about attributes in .NET, see [Extend metadata using attributes](/dotnet/standard/attributes/).
+
+## Examples
+This example shows how to print all custom attributes applied to the type definition:
+
+:::code language="csharp" source="~/snippets/csharp/System.Reflection.Metadata/CustomAttribute/Overview/CustomAttributeSnippets.cs" id="SnippetPrintAttributes":::
+
+ ]]></format>
+    </remarks>
   </Docs>
   <Members>
     <Member MemberName="Constructor">