c# - Custom Layer not drawing using ArcObjects?

I have a Customer layer which inherits BaseCustomLayer.

I add it to my MapControl via addLayer but the function public override void Draw(esriDrawPhase drawPhase, IDisplay Display, ITrackCancel trackCancel) is never hit.

The Custom Layer appears checked in the TOC.

I think I must be missing some initialization one-liner.

Answer

Here's a minimalist custom layer:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using ESRI.ArcGIS.ADF.BaseClasses;
using ESRI.ArcGIS.Geometry;
using ESRI.ArcGIS.Display;
using ESRI.ArcGIS.esriSystem;

namespace MapControlApplication1

{
    class CustLayer2: BaseCustomLayer
    {
        public override void Draw(esriDrawPhase drawPhase, IDisplay Display, ITrackCancel trackCancel)
        {
            System.Diagnostics.Debug.Print("drawing {0} {1}", drawPhase,  Environment.TickCount);
        }
    }
}

I created a new Project and choosing C#>ArcGIS>Extending ArcObjects>Mapcontrol Application, then added a new menuitem on the menu of MainForm with this:

private void testToolStripMenuItem_Click(object sender, EventArgs e)
{
    try
    {
        CustLayer2 layer = new CustLayer2();
        layer.Name = "cust layer2";
        axMapControl1.AddLayer(layer);
    }
    catch (Exception ex)

    {
        MessageBox.Show(this, ex.Message);
    }
}

When I run I see this output as I pan around the map:

drawing esriDPGeography 441416029
drawing esriDPGeography 441422207
drawing esriDPGeography 441433579