I needed to convert a HEX color code to a System.Drawing.Color, specifically a shade of Alice Blue as a background on a WPF form and found it took longer than expected to find the answer:
using System.Windows.Media;
--
System.Drawing.Color myColor = System.Drawing.ColorTranslator.FromHtml("#EFF3F7");
this.Background = new SolidColorBrush(System.Windows.Media.Color.FromArgb(myColor.A, myColor.R, myColor.G, myColor.B));