Gonçalo Ferreira’s Blog

On other day i was trying to use HashTable to display records in a combo box being the Key the Display Member and Value the ValueMember like so:

HashTable hash = new HashTable();
ComboBox ddlText = new ComboBox();

hash.Add("FirstKey", 1000);
hash.Add("SecondKey", 1005);            

ddlText.BeginUpdate();

ddlText.ValueMember = "Value";
ddlText.DisplayMember = "Key";
ddlText.DataSource = hash;

ddlText.EndUpdate();

But in order to bind an object to a ComboBox it has to implement IList or IListSource interface.

So i created a new class derived from HashTable implementing the IListSource interface:

public class EnhancedHashTable : Hashtable, IListSource
{
    public bool ContainsListCollection
    {
        get { return true; }
    }

    public IList GetList()
    {
        List list = new List();
        foreach (DictionaryEntry obj in this)
            list.Add(obj);

        return list;
    }
}

Using a Dictionary…

public class EnhancedDictionary:Dictionary, IListSource
{
    public bool ContainsListCollection
    {
      get { return true; }
    }

    public IList GetList()
    {
        List > list = new List>();
        foreach (KeyValuePair entry in this)
             list.Add(entry);

        return list;
    }
}

UPDATE: Looks like there is a simpler solution, instead of implementing this class. You simply use .NET 2.0 BindingSource class.