A function with a Bitmap

[RicercatoreSbadato]

What's happen exactly when I pass a Bitmap to a function in this way:

text_localization(EMP1);
public Bitmap text_localization( Bitmap EMP1 ) {}
??

It's the same thing to do this?

text_localization(ref EMP1);
public Bitmap text_localization( ref Bitmap EMP1 ) {}

 

[Fabien Bezagu]

When the ref keyword is present, you can change the reference passed to the
function.

Consider this sample :

void fct1()
{
ClassX obj1 = null;
Class obj2 = null;
fct(obj1, obj2);

// obj1 == null
// obj2 != null
}

void fct2(ClassX o1, ref ClassX o2)
{
if (o1 == null)
o1 = new ClassX();
if (o2 == null)
o2 = new ClassX();
}

Fabien

 

[RicercatoreSbadato]

ok, but my question was on the Bitmap Class. What I pass when I do so:

text_localization(EMP1);
public Bitmap text_localization( Bitmap EMP1 ) {}

??

 

[Fabien Bezagu]

I'm a bit confused and perhaps I don't understand exactly what's your
problem.

Since Bitmap is a class, and thus a reference type, you pass the reference
to the instance when simply passing it as parameter without the ref keyword.
If the question was "Is there a new instance of Bitmap created ?", the
answer is clearly "no".

Hope this helps.

Fabien

 

[RicercatoreSbadato]

yes, that was the answer I was looking for.
thank you.

 

[Ignacio Machin \( .NET/ C# MVP \)]

Hi,

It's a subtle differece , for one of the best explanation aroudn read this :
http://www.yoda.arachsys.com/csharp/parameters.html

in short the difference is that when use the "ref" you can change to what
instance the variable EMP1 refers to.

and in both cases you can change the instance reference by EMP1.


read the article, it's crystal clear there.


cheers,