C#

public interface IHistoryService
{
   bool Supported { get; }
 
   Document Document { get; }
}
 
public interface IValidationService
{
   bool Supported { get; }
 
   ReadOnlyCollection<ValidationError> ValidationErrors { get; }
}

public class DocumentViewer : Form, IHistoryService, IValidationService
{
   bool IHistoryService.Supported
   {
      get
      {
         return true;
      }
   } 
 
   bool IValidationService.Supported
   {
      get
      {
         return true;
      }
   } 
}

CA1033 : Microsoft.Design : Make 'DocumentViewer' sealed (a breaking change if this class has previously shipped), implement the method non-explicitly, or implement a new method that exposes the functionality of 'IDocumentInformationService.get_DocumentTemplateFullName():String' and is visible to derived classes.

Consider a base type that explicitly implements a public interface method. A type that derives from the base type can only access the inherited interface method through a reference to the current instance (this in C#) that is cast to the interface. If the derived type re-implements (explicitly) the inherited interface method, the base implementation is no longer accessible. The call through the current instance reference will invoke the derived implementation; this results in recursion and an eventual stack overflow.

public bool Supported
{
   get
   {
      return true;
   }
}