Whether NameObjectCollectionBase contains entries whose keys are not null.
using System; using System.Collections; using System.Collections.Specialized; public class MyCollection : NameObjectCollectionBase { private DictionaryEntry _de = new DictionaryEntry(); public DictionaryEntry this[ int index ] { get { _de.Key = this.BaseGetKey( index ); _de.Value = this.BaseGet( index ); return( _de ); } } public MyCollection() { } public void Add( String key, Object value ) { this.BaseAdd( key, value ); } public Boolean HasKeys { get { return( this.BaseHasKeys() ); } } } public class SamplesNameObjectCollectionBase { public static void Main() { MyCollection myCol = new MyCollection(); Console.WriteLine( "Initial state of the collection (Count = {0}):", myCol.Count ); PrintKeysAndValues( myCol ); Console.WriteLine( "HasKeys? {0}", myCol.HasKeys ); myCol.Add( "blue", "sky" ); Console.WriteLine( "Initial state of the collection (Count = {0}):", myCol.Count ); PrintKeysAndValues( myCol ); Console.WriteLine( "HasKeys? {0}", myCol.HasKeys ); } public static void PrintKeysAndValues( MyCollection myCol ) { for ( int i = 0; i < myCol.Count; i++ ) { Console.WriteLine( "[{0}] : {1}, {2}", i, myCol[i].Key, myCol[i].Value ); } } }