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How to return dynamic return types to methods? FROM#

I have a problem with the return type of the method.

The method returns a linq object, which currently returns the type tblAppointment. This method is shown below:

public tblAppointment GetAppointment(int id)
{
    var singleAppointment = (from a in dc.tblAppointments
                                                    where a.appID == id
                                                    select a).SingleOrDefault();
    return singleAppointment;

}

The problem is that tblAppointment is abstract and has many subtypes that inherit it. When I try to return an object that is of type "destinationTypeA" and calls the .GetType () method, it gives me the correct subtype, but when I try to access the properties, it allows me to access the parent properties, If I take the object and pass it to a new subtype object, then it works and allows me to access everything I need, but it seems messy.

var viewSingleAppointment = appointmentRepos.GetAppointment(appointmentId);

Debug.Write(viewSingleAppointment.GetType()); //returns type i want

if (viewSingleAppointment is tblSingleBirthAppointment)
{
    tblSingleBirthAppointment myApp = (tblSingleBirthAppointment)viewSingleAppointment; //need to do this to access TypeA properties for some reason

}

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+5
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        break;
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        break;
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public T GetAppointment<T>(int id) where T : tblAppointment
{
    var singleAppointment = (from a in dc.tblAppointments
                                                    where a.appID == id
                                                    select a).SingleOrDefault();
    return (T) singleAppointment;

}

:

SpecificAppointment app = GetAppointment<SpecificAppointment>(10);

:

var app = GetAppointment<SpecificAppointment>(10);

, .

, ( tblAppointment, ). , , , ...

+7

:

public T GetAppointment<T>(int id) where T : tblAppointment 
{
    var singleAppointment = dc.tblAppointments.SingleOrDefault(a => a.appID == id);
    return (T)singleAppointment;
}

...

+2

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class tblAppointment
{
    protected abstract void ProcessAppointment () ;
}

sealed class tblBirthAppointment
{
    protected override void ProcessAppointment ()
    {
        // `this` is guaranteed to be tblBirthAppointment
        // do whatever you need
    }
}

...


// will dispatch on runtime type
appointmentsRepo.GetAppointment (id).ProcessAppointment () ;
+2

:

public tblSingleBirthAppointment GetBirthAppointment(int id)
{
    var singleAppointment = GetAppointment(id);

    if (singleAppointment != null)
    {
        return (tblSingleBirthAppointment)singleAppointment;
    }

    return null;
}

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var viewSingleBirthAppointment = appointmentRepos.GetBirthAppointment(appointmentId);
+1

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