Argument of type ref int?

  • Thread starter Thread starter sheperson
  • Start date Start date
S

sheperson

Hi,
I have a stored procedure in my database and it has an argument of
type output (int).
When I create a dataset using VS2005, it creates a table adapter for
me and the Fill method has and argument of type
ref int?.
When I try to call the Fill method it prompts an error and says cannot
convert ref int to ref int?.
Does anyone know how should I call this Fill method?
Thanks in advance.
 
Hi,
I have a stored procedure in my database and it has an argument of
type output (int).
When I create a dataset using VS2005, it creates a table adapter for
me and the Fill method has and argument of type
ref int?.
When I try to call the Fill method it prompts an error and says cannot
convert ref int to ref int?.
Does anyone know how should I call this Fill method?
Click to expand...

Yes - supply it with a ref int? instead:

int? foo = null;
Fill (..., ref foo);

You can't do that if foo isn't nullable - for "ref" parameters, the
argument type (i.e. what you're calling the method with) has to match
the parameter type (i.e. what the method has declared) exactly.

Jon
 
And just to add to Jon’s reply. Think about what would happen if that
was allowed. In the example below the caller is sending a type
“DerivedClass” but the function being called is only required to
return a type of “BaseClass” so you can see how this would create a
problem.

class BaseClass
{
}

class DerivedClass : BaseClass
{
}

class Program
{
static void Main(string[] args)
{
DerivedClass n = new DerivedClass();
DoIt(ref n);
}

static void DoIt(ref BaseClass niceClass)
{
niceClass = new BaseClass();
}
}
 
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