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I created an app.config file and put the datasource in there incase it changes in the near future and i keep getting the null reference exception was unhandled.

use the new keyword as an object instance

but i have already imported the using system.configuration

and yet still. i have tried to catch but it seems not to work

public partial class LoginForm : Form
        //Main mnFrm;
        SqlConnection sqlConn = new SqlConnection(ConfigurationManager.ConnectionStrings["DbConn"].ToString());//the exception is thrown on this line when I run the program
        SqlDataReader sdr;
        SqlCommand sqlCmd = new SqlCommand();

        public LoginForm(Main mnFrm)
            //this.mnFrm = mnFrm;

I would appreciate the help guys thanks in advance
MuhammadUSman1 26-Jun-13 1:48am
I added solution please check it.

JoelonJada 26-Jun-13 8:08am
Thank you very much for that article. I will ask questions later.
qlConnection sqlConn = new SqlConnection(ConfigurationManager.ConnectionStrings["DbConn"].ToString());//the exception is thrown on this line when I run the program

in this line you write Key "DbConn" dose not exist in your config file are you write wrong spell there.
JoelonJada 26-Jun-13 1:57am
that is the variablename for the connectionstring in the app.config file for which ever database it is to connect to in future
MuhammadUSman1 26-Jun-13 2:01am
Please post your config file code here, or you make sure that the spell you using in Code "DbConn" is same in your config file
JoelonJada 26-Jun-13 4:37am
<add name="DbConn" providername="System.Data.SqlClient" connectionstring=" Data Source=popsy-pc; Initial Catalog=GEMSystem; Integrated Security=True; ">

MuhammadUSman1 26-Jun-13 6:42am
What is this?
JoelonJada 26-Jun-13 7:47am
Sorry I can't seem to figure out the tag for posting codes here...if you do please show me how
MuhammadUSman1 27-Jun-13 0:23am
If problem didn't solved yet. then please Past code of your config file. with dummy data.
Do you have a connection called "DbConn" in the ConnectionStrings section of your config file?
JoelonJada 26-Jun-13 1:44am
yes please i do
CHill60 26-Jun-13 8:56am
If you need further clarification from the OP please use the "Have a question or Comment?" link, don't post questions as Solutions
_Damian S_ 26-Jun-13 19:45pm
It wasn't a search for clarification... I was pointing the OP in the likely direction of his error... I prefer to guide people towards the answer rather than simply handing it to them on a plate.
You can add a settingsfile to your solution and set the connectionstring there.
Then you can acces the connectionstring from the settingfile.

using (SqlConnection sett = new SqlConnection(Settings.Default.Setting))
           //your code here;
JoelonJada 26-Jun-13 1:46am
Should i state this sett ing file as a global variable. Because i get the message the setting does not exist in the current context
Tom Wauters 26-Jun-13 2:51am
If you specifie it with a name, type as connectionString,scope: Application, and value as the connectionstring you want to use, you can just acces it as setting.Default."theNameofYourConnectionString"

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