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Public property GET issue in c# csharp c sharp .net

Posted on 2008-10-20
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Last Modified: 2013-12-17
Concrete class C_UserDefinedInstrument inherits from abstract class A_Instrument.

OK, so I try to SET a property on an instance of the concrete class, and while debugging one line of execution at a time, I noticed that execution goes into the GET and then SET of the property of the abstract class!

I expected execution to go only into the concrete class to SET the property, NOT into the GET and then SET of the property of the abstract class instead. Why is execution going into the abstract class, and why is it entering the GET part of the property at all when I called a SET?!

Is that really normal? Because I don't think it is.

Below is the following code:
1) Main Program
2) Abstract class A_Instrument
3) Concrete class C_UserDefinedInstrument

//
// 1) Main Program
//
class Program
    {
        static void Main(string[] args)
        {
            C_UserDefinedInstrument myInstrument;
 
            myInstrument = new C_UserDefinedInstrument(new GpibAddress(1, 2, "3"));
 
            //  SET-causing statment from the main program.
            myInstrument.PhysicalGpibAddress.AddressNumber = 5;
        }
    }
 
 
//
// 2) Abstract class
//
namespace Gpib
{
    abstract public class A_Instrument
    {
        private GpibAddress _physicalInstrumentGpibAddress;   
 
        protected A_Instrument(GpibAddress address)
        {
            System.Console.Out.WriteLine("A_Instrument constructor begin...");
            this._physicalInstrumentGpibAddress = address;
            System.Console.Out.WriteLine("A_Instrument constructor end.");
        }
 
        public GpibAddress PhysicalGpibAddress
        {
            get 
            {
                // Why does execution go here when I called SET?
                System.Console.Out.WriteLine("A_Instrument PhysicalGpibAddress get.");
                return this._physicalInstrumentGpibAddress; 
            }
            set 
            {
                System.Console.Out.WriteLine("A_Instrument PhysicalGpibAddress set.");
                this._physicalInstrumentGpibAddress = value; 
            }
        }
    }
}
 
 
//
// 3) Concrete Class
//
namespace Gpib
{
    class C_UserDefinedInstrument: A_Instrument, I_Instrument
    {
        private DateTime _createdOnThisDateAndTime;
        protected DateTime _modifiedOnThisDateAndTime;
        protected string _alias;
        private InstrumentState.states _state;
        private string _instrumentUniquenessKey;
 
        public C_UserDefinedInstrument(GpibAddress address) : base(address)
        {
            System.Console.Out.WriteLine("UserDefinedInstrument constructor begin...");
            this.PhysicalGpibAddress = address;            
            System.Console.Out.WriteLine("UserDefinedInstrument constructor end.");
        }
 
        GpibAddress PhysicalGpibAddress
        {
            get 
            {
                System.Console.Out.WriteLine("UserDefinedInstrument PhysicalGpibAddress get...");
                return base.PhysicalGpibAddress;
            }
            set 
            {
                // I expected execution to go here, but it doesn't.
                System.Console.Out.WriteLine("UserDefinedInstrument PhysicalGpibAddress set...");
                base.PhysicalGpibAddress = value;
            }
        }
 
        public string ReturnConnectionString
        {
            get { throw new Exception("Not implemented."); }
        }
    }
}

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Question by:yaronusa
3 Comments
 
LVL 16

Accepted Solution

by:
ororiole earned 250 total points
ID: 22762829
You want PhysicalGpibAddress of the concrete class to override the property of the abstract class right? And your property in the concrete is set to private by default. So it goes to the only Property it can
access, the public one in the abstract class.
Mark the concrete property with

public ovverrides GpibAddress PhysicalGpibAddress

and the abstract one with
public virtual  GpibAddress PhysicalGpibAddress

0
 
LVL 29

Assisted Solution

by:anarki_jimbel
anarki_jimbel earned 250 total points
ID: 22763258
Honestly, I didn't see any abstract in your abstract class. I.e., no abstract methods, props etc. What's the point for it to be abstract? Anyway, even if the class is abstract it does not mean all members are abstract. The class may have implemented properties and they can be used.

OK, now about your implemented class let's have a look at the code:

           set
            {
                // I expected execution to go here, but it doesn't.
                System.Console.Out.WriteLine("UserDefinedInstrument PhysicalGpibAddress set...");
                base.PhysicalGpibAddress = value;
            }

base.PhysicalGpibAddress = value; - you call the base class!
In the first part you call get trying to access the property:
base.PhysicalGpibAddress
 and then you are trying to set the value:
 = value.

And you can't expect anything else - the only way to access "_physicalInstrumentGpibAddress" variable is to enter abstract class property.
Does this fact causing any problems?
0
 

Author Closing Comment

by:yaronusa
ID: 31508043
Thanks! Yeah, I guess I missed the point of the abstract class. You folks gave me the information I need to now experiment with the code... thank you.
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