Yes, that sounds feasible. This means that you would have a Task instance for each Appointment instance, and have to maintain both of those instance whenever a property on your "hybrid"  class changes.

Brian, thank you for your reply. 

Here is my first attempt at a class to do this, inherting from SubObjectBase.

 I thought there would be a need to detect and handle a circular event cycle. For example:

1. task.Name is updated,
2. OnSubObjectPropChanged handles the task.Name change event an updates appt.Subject,
3. then an event is raised on the appt.Subject change
4. OnSubObjectPropChanged handles the appt.Subject change event and updates task.Name
5. cycle repeats at step 1

However, I'm happy to say the circular event cycle does not seem to be a problem, although I'm not sure why at this point.  Can you comment on why it does not have an endless circular event cycle? 

Would anybody have any suggestions for improvement(s) to the below?

----------

using System;
using Infragistics.Win.UltraWinSchedule;
using Infragistics.Shared;
using System.Diagnostics; // for Debug

public class TaskAppt : SubObjectBase
{
    public Task task;
    public Appointment appt;
    private Guid guid;

    public TaskAppt(string name)
    {
        task = new Task();
        appt = new Appointment(System.DateTime.Now, System.DateTime.Now + System.TimeSpan.FromDays(1));
        guid = System.Guid.NewGuid();
        task.Tag = this;
        appt.Tag = this;
        Name = name;
        task.StartDateTime = appt.StartDateTime;
        task.Duration = (TimeSpan)(appt.EndDateTime - appt.StartDateTime);

        this.task.SubObjectPropChanged += this.SubObjectPropChangeHandler;
        this.appt.SubObjectPropChanged += this.SubObjectPropChangeHandler;

        Debug.WriteLine(guid, " guid for newly created TaskAppt ");
    }

    public override string ToString()
    {
        System.Text.StringBuilder sb = new System.Text.StringBuilder();

        sb.Append("TaskAppt: Task "); sb.Append(task.Name); sb.Append(" ");
        sb.Append(task.StartDateTime.ToString()); sb.Append(" ");
        sb.Append(task.Duration.ToString()); sb.Append(" ");
        DateTime taskEnd = task.StartDateTime + task.Duration;
        sb.Append(taskEnd.ToString());
        sb.Append("; Appt "); sb.Append(appt.ToString());
        return sb.ToString();
    }

    public string Name
    {
        get { return task.Name; }
        set
        {
            Debug.WriteLine("In update Name");
            //Debug.WriteLine(guid, " before update name of TaskAppt ");
            //Debug.WriteLine(task.Name, " before update name of TaskAppt ");
            appt.Subject = task.Name = value;
            //Debug.WriteLine(guid, " after update name of TaskAppt ");
            //Debug.WriteLine(task.Name, " after update name of TaskAppt ");
        }
    }
    public DateTime StartDateTime
    {
        get { return appt.StartDateTime; }
        set
        {
            Debug.WriteLine("In update StartDateTime");
            appt.StartDateTime = task.StartDateTime = value;
        }
    }
    public DateTime EndDateTime
    {
        get { return appt.EndDateTime; }
        set
        {
            Debug.WriteLine("In update EndDateTime");
            appt.EndDateTime = value;
            TimeSpan ts = (TimeSpan)(appt.EndDateTime - appt.StartDateTime);
            task.Duration = ts;
            Debug.WriteLine(task.Duration, "in update EndDateTime set task.Duratoin ");
        }
    }

    public TimeSpan Duration
    {
        get { return task.Duration; }
        set
        {
            Debug.WriteLine("In update Duration");
            task.Duration = value;
            appt.EndDateTime = appt.StartDateTime + value;
        }
    }

    private void walkPci(PropChangeInfo pci)
    {
        int save = Debug.IndentLevel;
        while (pci != null)
        {
            System.Text.StringBuilder sb = new System.Text.StringBuilder();

            sb.Append("### Property Id: ");
            sb.Append(pci.PropId.ToString());
            sb.Append(", source: ");
            sb.Append(pci.Source.ToString());
            sb.Append(". type: ");
            sb.Append(pci.Source.GetType().ToString());
            sb.Append(", trigger: ");
            sb.Append(null == pci.Trigger ? "null" : pci.Trigger.ToString());

            Debug.WriteLine(sb.ToString());
            Debug.Indent();

            // Get the next PropChangeInfo object in the chain
            pci = pci.Trigger;
        }
        Debug.IndentLevel = save;
    }
    // Listens for property change notifications of the object's sub objects.
    protected override void OnSubObjectPropChanged(PropChangeInfo pci)
    {
        walkPci(pci);
        if (null != this.task && pci.Source == this.task)
        {
            Debug.Write("--- Source is task: ");
            Debug.Write(guid);
            Debug.WriteLine(this.task);
            switch ((TaskPropertyIds)pci.PropId)
            {
                case TaskPropertyIds.Name:
                    {
                        this.Name = this.task.Name;
                        //this.appt.Subject = this.task.Name;
                        break;
                    }
                case TaskPropertyIds.StartDateTime:
                    {
                        this.StartDateTime = this.task.StartDateTime;
                        //this.appt.Subject = this.task.Name;
                        break;
                    }
                case TaskPropertyIds.Duration:
                    {
                        this.Duration = this.task.Duration;
                        //this.appt.Subject = this.task.Name;
                        break;
                    }
                default:
                    break;
            }
        }
        else if (null != this.appt && pci.Source == this.appt)
        {
            Debug.Write("--- Source is appt: ");
            Debug.WriteLine(this.appt);
            switch ((PropertyIds)pci.PropId)
            {
                case PropertyIds.Subject:
                    {
                        this.Name = this.appt.Subject;
                        //this.task.Name = this.appt.Subject;
                        break;
                    }
                case PropertyIds.StartDateTime:
                    {
                        this.StartDateTime = this.appt.StartDateTime;
                        //this.task.Name = this.appt.Subject;
                        break;
                    }
                case PropertyIds.EndDateTime:
                    {
                        this.EndDateTime = this.appt.EndDateTime;
                        //this.task.Name = this.appt.Subject;
                        break;
                    }
                default:
                    break;

            }
        }

        // There is an overload to the 'NotifyPropChange' method
        // that just takes the passed in PropChangeInfo object.
        // This is useful if you want to pass the notification
        // along to this object's listeners 'as is'. In other words,
        // without creating a new PropChangeInfo to add to the
        // head of the chain (refer to above comments).
        this.NotifyPropChange(pci);
    }
} 

app3lam said:

Can you comment on why it does not have an endless circular event cycle?

Hi,

Let me know if you need any further assistance.

Regards,

Stefaniya