Check int

  • Thread starter Thread starter shapper
  • Start date Start date
S

shapper

Hello,

I have the following class:

public class Options {
public int Minimum { get; set; }
public int Maximum { get; set; }
} // Options

And I have something like:
Options o = new Options();
o.Minimum = 20;

How can I test here if Maximum was defined or not?
Do I need to make the property nullable Int32? and check if o.Maximum
== null?

Thanks,
Miguel
 
shapper said:
Hello,

I have the following class:

public class Options {
public int Minimum { get; set; }
public int Maximum { get; set; }
} // Options

And I have something like:
Options o = new Options();
o.Minimum = 20;

How can I test here if Maximum was defined or not?
Do I need to make the property nullable Int32? and check if o.Maximum
== null?
Click to expand...

You can use a Nullable<int> and then check "if (o.Maximum.HasValue) ...".

An alternative would be to initialize the property with a default
"impossible" value (such as int.MinValue), and then check against that value
to see if it has been assigned something valid.
 
It depends; if you are content to compare/contrast against the
*default* value (0 in this case), then that may suffice. But then you
won't know if they set o.Minimum = 0. And if you use Nullable<int>,
you won't know if they really meant null. One option is something
like:

private int? minimum;
public int Minimum {
get {return minimum.GetValueOrDefault();}
set {minimum = value;}
}

Now you can check if it has been assigned by looking at
minimum.HasValue. Or if you want to match PropertyGrid/serialization
standards patterns:

public bool ShouldSerializeMinimum() { return minimum.HasValue;}

(can be private for PropertyGrid, but needs to be public for
XmlSerializer)

Marc Gravell
C# MVP
 
shapper said:
Hello,

I have the following class:

public class Options {
public int Minimum { get; set; }
public int Maximum { get; set; }
} // Options

And I have something like:
Options o = new Options();
o.Minimum = 20;

How can I test here if Maximum was defined or not?
Do I need to make the property nullable Int32? and check if o.Maximum
== null?
Click to expand...

It *is* defined: its value is 0 by default. Do you mean, can you tell if
it was defined explicitly in the code? In that case, if its value is
something other than 0, obviously it was; if its value is 0, you have no
way to know whether someone set it explicitly.
 
   You can use a Nullable<int> and then check "if (o.Maximum.HasValue) ...".

    An alternative would be to initialize the property with a default
"impossible" value (such as int.MinValue), and then check against that value
to see if it has been assigned something valid.
Click to expand...

Thank You both,
Miguel
 
Harlan Messinger said:
It *is* defined: its value is 0 by default. Do you mean, can you tell if
it was defined explicitly in the code?
Click to expand...

"Defined" is being used poorly in this thread :-)
 
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