Learning C# properties from O'Relly book - sample code problem

  • Thread starter Thread starter Michael Hanson
  • Start date Start date
M

Michael Hanson

In a simple time class, int hour

/*
public int Hour // This works
{
get { return hour; }
set { hour = value; }
}
*/

// Automatic property?
public int Hour { get; set; } // This doesn't set hour !


// Client code
Time t = new Time(now);

int theHour = t.Hour;
Console.WriteLine("\nRetrieved the hour: {0}\n", theHour);
theHour++;
Console.WriteLine("\nUpdated the hour: {0}\n", theHour);
 
Michael said:
[...]
// Automatic property?
public int Hour { get; set; } // This doesn't set hour !
Click to expand...

Why would it? How would the compiler know that you want your member
field "hour" to be set by the property named "Hour"?

If you have explicit needs for your property implementation, then you
have to implement the property explicitly.

Pete
 
Peter Duniho said:
Michael said:
[...]
// Automatic property?
public int Hour { get; set; } // This doesn't set hour !
Click to expand...

Why would it? How would the compiler know that you want your member field
"hour" to be set by the property named "Hour"?

If you have explicit needs for your property implementation, then you have
to implement the property explicitly.

Pete
Click to expand...

OK thanks much
 
Michael said:
In a simple time class, int hour

/*
public int Hour // This works
{
get { return hour; }
set { hour = value; }
}
*/

// Automatic property?
public int Hour { get; set; } // This doesn't set hour !


// Client code
Time t = new Time(now);

int theHour = t.Hour;
Console.WriteLine("\nRetrieved the hour: {0}\n", theHour);
theHour++;
Console.WriteLine("\nUpdated the hour: {0}\n", theHour);
Click to expand...

That works in Interfaces for me the Auto Property, but it's not an Auto
Property. An Interface property get/set works like an Auto Property.

public Interface Look
{
string SeeWhat {get; set;}
}

Also something like Reshaper which I use will point out when you can use
an Auto Property and convert the standard property over to an Auto
Property. But it's conditional and Reshaper is not asking on every
property to an Auto Property


Public class Help
{
public string Name {get; set;}
}

I make a class like the one above all with auto properties all the time
when bringing Objects across the wire from a Web service to the client
like the Help class/object.

I think it may be in certain situations that you can use the Auto property.


Also from what I have seen Reshaper work, it looks at a class like Help
class and if the property is a standard property it will ask to auto
convert it.

So, I guess I am saying you have to find out under what conditions can
you use an auto property.
 
In a simple time class, int hour

/*
public int Hour // This works
{
get { return hour; }
set { hour = value; }
}
*/

// Automatic property?
public int Hour { get; set; } // This doesn't set hour !
Click to expand...

The whole point of an automatic property is to prevent you from ever seeing
or touching the backing variable. When you use automatic properties, you
must always reference them via the property itself.
 
Just the setter needs a private _hour member as the getter is still a magic
member.

Michael Hanson said:
Peter Duniho said:
Michael said:
[...]
// Automatic property?
public int Hour { get; set; } // This doesn't set hour !
Click to expand...

Why would it? How would the compiler know that you want your member
field "hour" to be set by the property named "Hour"?

If you have explicit needs for your property implementation, then you
have to implement the property explicitly.

Pete
Click to expand...

OK thanks much
Click to expand...
 
Hillbilly said:
Just the setter needs a private _hour member as the getter is still a
magic member.
Click to expand...

The setter cannot be provided a private "hour" member without explicitly
implementing the getter. You can't have both the private "hour" member
_and_ "a magic member" (by which I assume you mean the hidden,
auto-generated backing field that is created for an auto-implemented
property).

Pete
 
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