public MemoryConnectionProperties()

public Geodatabase GetMemoryGeodatabase()
{
  // Creates the default memory geodatabase if not exist or connects to an existing one if already exists
  Geodatabase memoryGeodatabase = new Geodatabase(new MemoryConnectionProperties());

  // Creates schema
  SchemaBuilder schemaBuilder = new SchemaBuilder(memoryGeodatabase);
  schemaBuilder.Create(new TableDescription("MyTable", new List<FieldDescription>()));
  schemaBuilder.Build();

  return memoryGeodatabase;
}