cannot convert from int to ref object

[Wilfried Mestdagh]

Hello,

probably a beginners question :)

I have this code sample in VB:
if (objResults.Ite m(1).etc
Translate this into C#
if (objResults[1].etc

But compiler complains about the index '1' with: cannot convert from int to
ref object. So what I do wrong here ? (objResults is a returned object from
MapPoint, but that does not matter I think).

--
rgds, Wilfried
http://www.mestdagh.biz

[Morten Wennevik]

Hi Wilfried,

I'm not sure what happens here, but VB is often less strict about
conversions where C# needs explicit casts.

What exactly is an objResults? and what does its Item collection return?

Basically, some more code would be nice :)
--
Happy Coding!
Morten Wennevik [C# MVP]

[Marcin Grzębski]

Hi Wilfried,

Hello,

probably a beginners question :)

I have this code sample in VB:
if (objResults.Ite m(1).etc
Translate this into C#
if (objResults[1].etc

But compiler complains about the index '1' with: cannot convert from int to
ref object. So what I do wrong here ? (objResults is a returned object from
MapPoint, but that does not matter I think).

If VB "Item" needs "ref object" parameter, then you can declare:

object objIndex=1;

.... and pass it by reference as follow:

objResulrs[ref objIndex].etc

HTH

Marcin

[Wilfried Mestdagh]

Hi Marcin and Morton,

Thanks for reply, but dont work. I can access the index in Delphi8 but it
give me other code completitions. So I assume the help and the example are
out of date. Will check that out first.

rgds, Wilfried

[Wilfried Mestdagh]

Hi,

I found out (reading some other likewise questions) how, but dont
understeand wy you can in VB just do objResults.Item (0).etc.. and in C# need
to use new object and GetEnumerator() etc. Can someone explain this to me ?

Result = objResults.GetE numerator();
while (Result.MoveNex t()) {
if(Result.Curre nt is MapPoint.Locati on) {
Loc = (MapPoint.Locat ion)Result.Curr ent;
if(Loc.StreetAd dress != null)
Console.WriteLi ne(Loc.StreetAd dress.Value);
}
}

rgds, Wilfried
http://www.mestdagh.biz

[Jon Skeet [C# MVP]]

Wilfried Mestdagh <Wi************ **@discussions. microsoft.com> wrote:

I found out (reading some other likewise questions) how, but dont
understeand wy you can in VB just do objResults.Item (0).etc.. and in C# need
to use new object and GetEnumerator() etc. Can someone explain this to me ?

Result = objResults.GetE numerator();
while (Result.MoveNex t()) {
if(Result.Curre nt is MapPoint.Locati on) {
Loc = (MapPoint.Locat ion)Result.Curr ent;
if(Loc.StreetAd dress != null)
Console.WriteLi ne(Loc.StreetAd dress.Value);
}
}

It would help if you'd give us a full program. Chances are you can just
use objResults[0] from C#, but as we don't know what objResults are
from your post, that's just a guess.

To iterate through, however, you don't need to call GetEnumerator()
directly in your code. You can use a foreach statement:

foreach (MapPoint.Locat ion loc in objResults)
{
if (loc.StreetAddr ess != null)
{
Console.WriteLi ne (loc.StreetAddr ess.Value);
}
}

That's assuming the results only contain locations. If you want to only
use MapPoint.Locati on objects, and the result contains others, you'd
use:

foreach (object o in objResults)
{
MapPoint.Locati on loc = o as MapPoint.Locati on;

if (loc != null && loc.StreetAddre ss != null)
{
Console.WriteLi ne (loc.StreetAddr ess.Value);
}
}

--
Jon Skeet - <sk***@pobox.co m>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too

[Wilfried Mestdagh]

Hello Jon,

You can use a foreach statement:
Thanks for your reply, this helped me a lot. Is lot more simplier :)
MapPoint.Locati on loc = o as MapPoint.Locati on;
if (loc != null && loc.StreetAddre ss != null)
So I see, if o is not a Location object, then the 'o as' returns null. So
not needed to play around with exception blocks here. Nice :)
foreach (object o in objResults)
{
MapPoint.Locati on loc = o as MapPoint.Locati on;
I see this programming style often. I'm used to declare al local stack
variables in the beginning of a function. Is this way not setting up stack
frames over and over again in a loop, or is this no matter in NET ?
It would help if you'd give us a full program. Chances are you can just
use objResults[0] from C#, but as we don't know what objResults are
from your post, that's just a guess.

It is only a little experiment with Mappoint in C# to learn the IDE /
programming. I'm not new to programming but very new to NET. This is complete:

private void stratenToolStri pMenuItem_Click (object sender, EventArgs
e)
{
MapPoint.Locati on objLoc;
MapPoint.Locati on Loc;
MapPoint.FindRe sults objResults;
MapPoint.Pushpi n PP;
System.Collecti ons.IEnumerator Result;

objLoc = MP.ActiveMap.Ge tLocation(Lat, Lon, Alt);
objLoc.GoTo();

// check if we are on a street
PP = MP.ActiveMap.Ad dPushpin(objLoc , "Kieken");
PP.Symbol = 1;

objResults =
MP.ActiveMap.Ob jectsFromPoint( MP.ActiveMap.Lo cationToX(objLo c),
MP.ActiveMap.Lo cationToY(objLo c));

foreach (object o in objResults) {
Loc = o as MapPoint.Locati on;

if(Loc != null && Loc.StreetAddre ss != null)
Console.WriteLi ne("value " + Loc.StreetAddre ss.Value);
else
Console.WriteLi ne("--- not mappoint.locati on object ---");
}
}

thx, Wilfried
http://www.mestdagh.biz

[Jon Skeet [C# MVP]]

Wilfried Mestdagh <Wi************ **@discussions. microsoft.com> wrote:

You can use a foreach statement:

Thanks for your reply, this helped me a lot. Is lot more simplier :)

MapPoint.Locati on loc = o as MapPoint.Locati on;
if (loc != null && loc.StreetAddre ss != null)

So I see, if o is not a Location object, then the 'o as' returns null. So
not needed to play around with exception blocks here. Nice :)

Yes. You could use "if (o is MapPoint.Locati on)" and then cast, but
using "as" is cheaper (because it only needs to do the test once).

foreach (object o in objResults)
{
MapPoint.Locati on loc = o as MapPoint.Locati on;

I see this programming style often. I'm used to declare al local stack
variables in the beginning of a function. Is this way not setting up stack
frames over and over again in a loop, or is this no matter in NET ?

No, all local variables are set up in IL code just once when you enter
the method. Declaring at the point of first use makes the point of the
variable clearer, as well as allowing you to use the same name in
multiple places without creating conflicts.

It would help if you'd give us a full program. Chances are you can just
use objResults[0] from C#, but as we don't know what objResults are
from your post, that's just a guess.

It is only a little experiment with Mappoint in C# to learn the IDE /
programming. I'm not new to programming but very new to NET. This is complete:

It's not really complete. It's a complete method, but not a complete
program. Then again, without the MapPoint API it's hard to know exactly
what the types involved do - do you have a reference URL to the API for
MapPoint.FindRe sults? (If MapPoint is a namespace, btw, putting a
"using" statement at the top of your class would allow you to refer to
the classes just as "Location", "FindResult s" etc - much more
readable.)

--
Jon Skeet - <sk***@pobox.co m>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too

[Wilfried Mestdagh]

Hello Jon,

Thanks for your reply. This si a URL with the method I use:

http://msdn.microsoft.com/library/de...indResults.asp

rgds, Wilfried

[Wilfried Mestdagh]

Hello Jon,

"using" statement at the top of your class would allow you to refer to
the classes just as "Location", "FindResult s" etc - much more
readable.)

Yes I know, but if I do that with MapPoint the compiler complains about an
ambiguous reference called 'Application'.

rgds, Wilfried