Passing a Null to Web Method

[J. L. Goddard]

1) Do c# web methods support default parameters ?


2) Can a web method, or a c# method such as:

public nullTest( int i )
{
return i++;
}

Can the web service consumer pass in a value of nullTest(null) ?


3) What if the web service is passing in a series of records where some
of the data for that parameter is null ? How should a null be passed
to the web service ?

 

[Razzie]

1) No. See http://blogs.msdn.com/csharpfaq/archive/2004/03/07/85556.aspx for
more info.
2) No. Maybe in Framework 2.0 where nullable variables or how you call it,
are supported. If the parameter type is an object, you can of course, pass a
null value.
3) Not sure I understand what you mean

 

[novelle.vague]

Razzie wrote:

Thanks. That's a good blog.

Unfortunately for us web methods don't support overloading !

So for a consumer of a web service, he has to account for all parameters
with 'dummy data' I guess...

That means if his value is null, for an int, and he wants to pass a record
to me with a web service/method, he has to make up a value like 0, and use
that.

That's not good integrity.

 

[William Stacey [MVP]]

Not sure I understand the question fully. But you could box the int in an
object and pass that or null ( I think ) or create a DBInt struct value type
like in Anders H. C# book (I just saw the code a bit.)

 

[novelle.vague]

Not sure I understand the question fully. But you could box the int in an
object and pass that or null ( I think ) or create a DBInt struct value
type like in Anders H. C# book (I just saw the code a bit.)

So are you saying given:

public int NullTest(int i)
{
returns i++;
}

I could say:


object o = null; // box null into an object box
int value2 = (int) o; // unbox into value2
public int NullTest(value2); // ???

Or should I configure NullTest() like:

public int NullTest(obj o)
{
returns ((int) o) ++ ;
}

And call it with

object o = null;
int j = NullTest(o); // ???

Because a datatype o can be null, but a datatype int cannot accept a null
value when passed in as a parameter ?

 

[Jeff Relf]

Hi novelle.vague ( Maestro Bailo ),

You asked if nullTest() could call this:

nullTest( int i ) { return i ++ ; }

If it's like C++, the answer is no.

nullTest() with no parameters would give a compile-time error.

But, if " i " is a global, for example,
you could overload nullTest() like this:

nullTest() { return i ++ ; }

nullTest( int J ) { return i = ++ J ; }

Re: Your: nullTest( null ),

NULL is a macro in C++, it's defined as 0 ( Zero ).

Did you mean: nullTest( void ) ?

You asked: <<
3) What if the web service is passing in
a series of records where some
of the data for that parameter is null ?

How should a null be passed to the web service ? >>

Create overloaded functions ?

Re: http://kentpsychedelic.blogspot.com ,

Your blog really rocks. You're a genius Bailo.

But my FireFox .9 was caching it...
I wasn't seeing the latest version.
( I think I've fixed that now )

Did you have a stroke ?