Slide 1

Attributes for Interoperation

Note: This section is applicable only to the Microsoft .NET implementation of C#.

Interoperation with COM and Win32 components

The .NET run-time provides a large number of attributes that enable C# programs to interoperate with components written using COM and Win32 DLLs. For example, the DllImport attribute can be used on a static extern method to indicate that the implementation of the method is to be found in a Win32 DLL. These attributes are found in the System.Runtime.InteropServices namespace, and detailed documentation for these attributes is found in the .NET runtime documentation.

Slide 2

Interoperation with other .NET languages

The IndexerName attribute

Indexers are implemented in .NET using indexed properties, and have a name in the .NET metadata. If no IndexerName attribute is present for an indexer, then the name Item is used by default. The IndexerName attribute enables a developer to override this default and specify a different name.

 namespace System.Runtime.CompilerServices.CSharp
 {
     [AttributeUsage(AttributeTargets.Property)]
     public class IndexerNameAttribute: Attribute
     {
         public IndexerNameAttribute(string indexerName) {...}
         public string Value { get {...} } 
     }
 }

Ref:- https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/language-specification/attributes#attributes-for-interoperation