Question

There isn’t one called Pens, that’s for sure, but it’s too odd not to find it. Is it really absent, or am I being blind?

(I’m just looking for a convenience class – for example, Colors.Red and Brushes.Red is there, but for pens the shortest appears to be new Pen(Brushes.Red, 1))

Answer 1

There is not the associated Pens class because a Pen is identified by both a Brush and a Thickness rather than just one property.

If you have a need for a set of standard pens (based on some thickness) then you will have to create your own. Another approach would be to create a code generator to supply the appropriate pens.

Here is an example of a class which adds a Pen for each default Brush:

public class DefaultPens
{
    private Dictionary<Brush, Pen> pens;

    public double Thickness
    {
        get;
        private set;
    }

    // used like defaultPens[Brushes.Red]
    public Pen this[Brush brush]
    {
        get { return this.pens[brush]; }
    }

    public DefaultPens(double thickness)
    {
        this.pens = typeof(Brushes).GetProperties(BindingFlags.Static)
                                   .Where(pi => pi.PropertyType == typeof(Brush))
                                   .Select(pi => pi.GetValue(null, null))
                                   .ToDictionary(
                                       b => b,
                                       b => new Pen(b, thickness));
        this.Thickness = thickness;
    }
}