C# .NET Template with IPrimitiveCommandEvents Class

/*--------------------------------------------------------------------------------------+
 * Microstation C# dotNET Template
 * 
 * Taken from SDK Examples and modified.
+--------------------------------------------------------------------------------------*/
using System;
using System.Collections.Generic;
using System.Windows.Forms;
using BMW=Bentley.MicroStation.WinForms;
using BMI=Bentley.MicroStation.InteropServices;
using BCOM=Bentley.Interop.MicroStationDGN;

namespace MS_dotNET_Template
{

/// <summary>When loading an AddIn MicroStation looks for a class
/// derived from AddIn.</summary>
[Bentley.MicroStation.AddInAttribute (KeyinTree="MS_dotNET_Template.Commands.xml", MdlTaskID="MS_dotNET_Template")]
public sealed class MS_dotNET_Template : Bentley.MicroStation.AddIn
{
	static MS_dotNET_Template s_App = null;

	/// <summary>Private constructor required for all AddIn classes derived from
	/// Bentley.MicroStation.AddIn.</summary>
	private MS_dotNET_Template ( System.IntPtr mdlDesc ) : base(mdlDesc)
	{
		s_App = this;
	}

	internal static MS_dotNET_Template Instance
	{
		get { return s_App; }
	}

	protected override int Run ( System.String[] commandLine )
	{
		return 0;
	}
}  // End of MS_dotNET_Template class


/// <summary>Class used for running key-ins. The key-ins
/// XML file provides the name of the class and the methods.
/// </summary>
public class KeyinCommands
{
    /*********************************************************************************
 * Template_Key-In
 * 
 * Command: dotNETTemplate
 *
 * Description: Template Key-In. Runs the IPrimitiveCommandEvents class
 * 
 *********************************************************************************/
    public static void Template_KeyIn(System.String uparsed)
    {
        BMI.Utilities.ComApp.CommandState.StartPrimitive(new Template_Primitive_Event_Class());
    }
}  // End of KeyinCommands


/// <summary>
/// Template IPrimitiveCommandEvents implemented class.
/// 
/// Additional code is added into this class as an example. It
/// follows the "Line Element Creation Command" Example provided
/// in the Microstation VBA Helpfile.
/// </summary>
public class Template_Primitive_Event_Class : BCOM.IPrimitiveCommandEvents
{
    // Application variable
    private BCOM.Application app = BMI.Utilities.ComApp;

    // Variables used in Example Code
    private BCOM.Point3d[] m_atPoints = new BCOM.Point3d[2];
    private int m_nPoints;

    /// <summary>
    /// Required Methods
    /// </summary>
    public void Cleanup() { }
    public void DataPoint(ref BCOM.Point3d pt, BCOM.View view) 
    {
        // Example Code
        if (m_nPoints == 0)
        {
            app.CommandState.StartDynamics();
            m_atPoints[0] = pt;
            m_nPoints = 1;
            app.ShowPrompt("Place end point: ");
        }
        else if (m_nPoints == 1)
        {
            m_atPoints[1] = pt;
            BCOM.LineElement oEl = app.CreateLineElement1(null, m_atPoints);
            app.ActiveModelReference.AddElement(oEl);
            oEl.Redraw();
            m_atPoints[0] = m_atPoints[1];
        }
    }
    public void Dynamics(ref BCOM.Point3d pt, BCOM.View view, BCOM.MsdDrawingMode DrawMode) 
    {
        // Example Code
        if (m_nPoints == 1)
        {
            m_atPoints[1] = pt;
            BCOM.LineElement oEl = app.CreateLineElement1(null, m_atPoints);
            oEl.Redraw(DrawMode);
        }
    }
    public void Keyin(string Keyin) { }
    public void Reset() { app.CommandState.StartDefaultCommand(); }
    public void Start() 
    {
        app.ShowCommand("MS_dotNET_Template: ");
        app.ShowPrompt("Select start of line: ");
    }
}
}  // End of the namespace

<?xml version="1.0" encoding="utf-8" ?>
<KeyinTree xmlns="http://www.bentley.com/schemas/1.0/MicroStation/AddIn/KeyinTree.xsd">
    <RootKeyinTable ID="root">
      <Keyword CommandClass="MacroCommand" CommandWord="dotNETTemplate"></Keyword>
    </RootKeyinTable>

    <SubKeyinTables>
    </SubKeyinTables>

    <KeyinHandlers>
        <KeyinHandler Keyin="dotNETTemplate"
            Function="MS_dotNET_Template.KeyinCommands.Template_KeyIn"/>
    </KeyinHandlers>
</KeyinTree>