How do I send custom property at receiver end in outllok addin

See more:

VSTO

Outlook

AddIn

C#6.0

Hi ,
I Created Addin in VSTO there is on problem can you please help me for this,the Problem is i created separate region in Appointment there i added two drop-down and i want to send the selected drop-down value with that region at receiver side i also install this addin on there system but the drop-down value is not getting what i selected here.
Can you please help me on this.#VSTO ,#csharp
I am using outlook 16 and VSTO addin.

What I have tried:

private void ItemSend_Send(object Item, ref bool Cancel)
        {
            try
            {
                Outlook.UserProperty _activityTrackertyoe = app_Item.UserProperties.Add("ActivityTrackerType", Outlook.OlUserPropertyType.olText,true, 1);
                _activityTrackertyoe.Value = ActivityTrackerType.Text;
                Outlook.UserProperty _subType = app_Item.UserProperties.Add("ActivityTrackerSubType", Outlook.OlUserPropertyType.olText,true, 1);
                _subType.Value = ActivityTrackerSubType.Text;
                app_Item.Body = ActivityTrackerType.Text + "<<<->>>>" + ActivityTrackerSubType.Text;
                app_Item.PropertyAccessor.SetProperty("http://schemas.microsoft.com/mapi/string/{00020386-0000-0000-C000-000000000046}/X-{ActivityTrackerType}", ActivityTrackerType.Text);
                app_Item.PropertyAccessor.SetProperty("http://schemas.microsoft.com/mapi/string/{00020386-0000-0000-C000-000000000046}/X-{ActivityTrackerSubType}", ActivityTrackerSubType.Text);
                app_Item.Save();
             
             
                //var myPages =   app_Item.GetInspector.ModifiedFormPages;
                //var myCtrl1 = myPages("ActivityTracker").Controls("ActivityTrackerType");
                //var  myCtrl2 = myPages("ActivityTracker").Controls("ActivityTrackerSubType");
                //myCtrl1.Enabled = true;
                //myCtrl1.Value = ActivityTrackerType.Text;
                //myCtrl2.Enabled = true;
                //myCtrl2.Value = ActivityTrackerSubType.Text;
                app_Item.Display();
                app_Item.Send();
                MessageBox.Show("Sent"+ _activityTrackertyoe.Value+"sub"+ _subType.Value);
            }
            catch (Exception)
            {
                throw;
            }
        
        }