In order to add custom data to an appointment, you need to create your own class derived from Appointment. You can add whatever additional properties you need to the derived class.

The sample below demonstrates how to do this.

class MyAppointment : Appointment
{
  public MyAppointment()
  {
    customData = 5;
  }

  public int CustomData
  {
    get { return customData; }
    set { customData = value; }
  }

  private int customData;
}
 

Use the Calendar.InteractiveItemType property to specify that items from your class should be instantiated whenever the user creates items interactively. In this case you have to ensure that your class provides parameterless constructor as stated in the Planner.NET documentation.

I hope that helps
Stoyan

my data is not saved in the file, what I should to to save my own property in the method SaveTo of Schedule ?

Thank You