implicit conversion

[docschnipp]

Hi,

I have an object that manages a kind of Variant type. For comfort reasons I
want to have the possibility to do this:

MyPropclass prop = new MyPropclass();
string m = "blabla";

prop = m;

How can I do this? Is there a way to overwrite "="? Or must I extend "string"?

Thanks
doc

[ssamuel]

Re: implicit conversion

doc,

Technically, you'd have to extend String. I'm not sure if base types
are declared partial in 2.0, but even if they are, that's probably a
bad idea.

You'd do much better to have a MyPropclass(str ing) constructor, or
maybe a static MyPropclass MyPropclass.Fac tory(string) method. If
MyPropclass encapsulates substantially more than a string, void
MyPropclass.Ass imilate(string) may be appropriate. Alternately, if
you're into "clean" language constructs, you can write static
MyPropclass operator+(strin g, MyPropclass) and end up with:

MyPropclass prop = new MyPropclass();
[ ... do stuff with prop ... ]
string m = "mystring";
prop += m;


Does that help?


Stephan


docschnipp wrote:

Hi,
>
I have an object that manages a kind of Variant type. For comfort reasons I
want to have the possibility to do this:
>
MyPropclass prop = new MyPropclass();
string m = "blabla";
>
prop = m;
>
How can I do this? Is there a way to overwrite "="? Or must I extend "string"?
>
Thanks
doc

[Martin Z]

Re: implicit conversion

Depends. Will the user be making changes to the string object before
it is put into the propclass? Or can the "new MyPropclass();" be
dropped? That is

MyPropclass prop = "blabla"; //constructs a MyPropclass object out of
the string

use implicit user-defined conversion operators:

http://www.c-sharpcorner.com/Languag...nCSharpRVS.asp -
scroll down to "user-defined".

I'm not positive it'll work, haven't tried it myself, but I *think*
that's what they're for.

docschnipp wrote:

Hi,
>
I have an object that manages a kind of Variant type. For comfort reasons I
want to have the possibility to do this:
>
MyPropclass prop = new MyPropclass();
string m = "blabla";
>
prop = m;
>
How can I do this? Is there a way to overwrite "="? Or must I extend "string"?
>
Thanks
doc

[docschnipp]

Re: implicit conversion

Hi Stephan,

"ssamuel" wrote:

doc,
>
Technically, you'd have to extend String. I'm not sure if base types
are declared partial in 2.0, but even if they are, that's probably a
bad idea.

Agree, sounds bad or at least not very elegant.

You'd do much better to have a MyPropclass(str ing) constructor, or
maybe a static MyPropclass MyPropclass.Fac tory(string) method. If
MyPropclass encapsulates substantially more than a string, void
MyPropclass.Ass imilate(string) may be appropriate. Alternately, if
you're into "clean" language constructs, you can write static
MyPropclass operator+(strin g, MyPropclass) and end up with:
>
MyPropclass prop = new MyPropclass();
[ ... do stuff with prop ... ]
string m = "mystring";
prop += m;

I am sticking with a bunch of overloaded ".Set(#sometype # newValue)"
functions. When I am deeper in C# I will try to come up with something nicer,
but for now it is okay.

Thanks for your help,

doc

[Göran Andersson]

Re: implicit conversion

docschnipp wrote:

Hi,
>
I have an object that manages a kind of Variant type. For comfort reasons I
want to have the possibility to do this:
>
MyPropclass prop = new MyPropclass();
string m = "blabla";
>
prop = m;
>
How can I do this? Is there a way to overwrite "="? Or must I extend "string"?
>
Thanks
doc
>

Implicit conversions works just fine. Example:

public class Demo {

private string _value;
public Demo(string value) {
_value = value;
}
public static implicit operator Demo(string value) {
return new Demo(value);
}

}

Usage:

Demo d = "asdf";