Layer definition. Layers are a way to group objects so that the groups can have common formatting. For example, you may want your objects to show up in one color and your dimensions to show in another. Create a separate layer for each, then you can change all the dimensions or all the objects at the same time. You may show or hide layers, change the color, lineweight, or linetype. Layers are utilized often to make drawings easier to read.

'Declaration
 
Public Class Layer 
   Implements devDept.Graphics.IKeyedCollectionDisposableItem(Of Layer), devDept.Graphics.IKeyedCollectionItem(Of Layer), devDept.Graphics.INotifyKeyChanged 

public class Layer : devDept.Graphics.IKeyedCollectionDisposableItem<Layer>, devDept.Graphics.IKeyedCollectionItem<Layer>, devDept.Graphics.INotifyKeyChanged