class files into dll

[Hrvoje Voda]

I have created a project solution with two class projects.

One is used to give information about user and the other one is a dataset
connection properties.

The class with users has reference to dataset.

Now, I created an dll of those project solution.

But, when I call a public function "SetConnectionS tring(string sConnString)"
in users class I get an error : Object reference not set to an instance of
an object !

Why ?

public class in users :

using System;

using System.Collecti ons;

using System.Componen tModel;

using System.Windows. Forms;

using LoginDb;

namespace UserLogin

{

public class Logon

{

LoginDb.Db db = null;



public Logon()

{


}

public void SetConnectionSt ring(string sConnString)

{

db = new Db(sConnString) ;

}



}

}



Hrcko

[Jon Skeet [C# MVP]]

Re: class files into dll

Hrvoje Voda <hrvoje.voda@lu atech.com> wrote:[color=blue]
> I have created a project solution with two class projects.
>
> One is used to give information about user and the other one is a dataset
> connection properties.
>
> The class with users has reference to dataset.
>
> Now, I created an dll of those project solution.
>
> But, when I call a public function "SetConnectionS tring(string sConnString)"
> in users class I get an error : Object reference not set to an instance of
> an object !
>
> Why ?[/color]

Could you post a short but complete program which demonstrates the
problem?

See http://www.pobox.com/~skeet/csharp/complete.html for details of
what I mean by that.

The obvious answer is that you may be calling SetConnectionSt ring on a
null reference rather than on a reference to an instance of Logon.
Without seeing the calling code, it's impossible to say.

It's unlikely to be anything to do with doing it in a separate library
though.

--
Jon Skeet - <skeet@pobox.co m>

http://www.pobox.com/~skeet

If replying to the group, please do not mail me too

[Ziga Jakhel]

Re: class files into dll

Hrcko:

1) I presume the sConnString is not null?

2) Judging by the code you posted this sounds like a problem in the LoginDB
Class constructor.

Try putting the db = new DB(sConnString) into a try... catch block and/or
step through what exactly happens in the DB constructor.
Review the exception information and stacktrace on where exactly the error
occured.


Bok,

Ziga Jakhel



"Hrvoje Voda" <hrvoje.voda@lu atech.com> wrote in message
news:d7hdta$4bm $1@ss405.t-com.hr...[color=blue]
>I have created a project solution with two class projects.
>
> One is used to give information about user and the other one is a dataset
> connection properties.
>
> The class with users has reference to dataset.
>
> Now, I created an dll of those project solution.
>
> But, when I call a public function "SetConnectionS tring(string
> sConnString)" in users class I get an error : Object reference not set to
> an instance of an object !
>
> Why ?
>
> public class in users :
>
> using System;
>
> using System.Collecti ons;
>
> using System.Componen tModel;
>
> using System.Windows. Forms;
>
> using LoginDb;
>
> namespace UserLogin
>
> {
>
> public class Logon
>
> {
>
> LoginDb.Db db = null;
>
>
>
> public Logon()
>
> {
>
>
> }
>
> public void SetConnectionSt ring(string sConnString)
>
> {
>
> db = new Db(sConnString) ;
>
> }
>
>
>
> }
>
> }
>
>
>
> Hrcko
>
>[/color]