Question

I’m dealing with a class written by a third party that implements System.Collections.CollectionBase:

public class Palette : CollectionBase, ICloneable

The only rub I have with it is that I can only access its elements via integer index: [0], [1], [2]. I need to enhance this class’ functionality so that I can access an element via a string so I can do something like this:

["asian"] = Color.Yellow, ["black"] = Color.Black, ["White"] = Color.White

So I attempted to wrap this up in my own class. So far I have:

public class NamedPalette : Palette
{
    private Dictionary<string, PaletteEntry> paletteEntries =
        new Dictionary<string, PaletteEntry>();

    public PaletteEntry this[string key]
    {
        get { return paletteEntries[key]; }
        set { paletteEntries.Add(key, value); }
    }
    public NamedPalette()
    {

    }
}
public class PaletteEntry
{
    private Color color;
    private Color color2;
    public PaletteEntry(Color color, Color color2)
    {
        this.color = color;
        this.color2 = color2;
    }
}

Am I on the right track here? Not sure what to do next.

Answer 1

You’re on the right track.

Just change your set accessor to check for existing entries by replacing your line set { paletteEntries.Add(key, value); } with set {palletteEntries[key] = value;}

All you then need to start doing is to add PalletteEntries to your NamedPallette and using them, such as

NamedPalette myPallette = new NamedPallette();
PalletteEntry myPalletteEntry = new PalleteEntry(Color.Red, Color.Black);
myPallette ["myColors"] = myPalletteEntry;
var fetchedEntry = myPallette["myColors"];