how to read the connection string from web.config file in asp.net using c#

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C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data.SqlClient;
using System.Configuration;
using System.Data;

namespace Sample2
{
    public class MyFunctions
    {
        string connstring = ConfigurationManager.ConnectionStrings["EpfConnectionString"].ConnectionString;
        SqlConnection con = new SqlConnection(connstring);  //error in connstring 
       
}
}

#Above is my class where it is showing error as Error 12 A field initializer cannot reference the non-static field, method, or property.
@error at SqlConnection con = new SqlConnection(connstring);

Below is my web.config code

C#

<connectionStrings>
    <add name="EpfConnectionString" connectionString="Data Source=ACS-MUMADHD-25\SQLEXPRESS;Initial Catalog=epf;Persist Security Info=True;User ID=sa;Password=sa2008" providerName="System.Data.SqlClient" />
  </connectionStrings>

Experts Please help...
Millions of thanks in advance

Posted 10-Aug-15 20:02pm

harshil gandhi

Updated 10-Aug-15 20:07pm

v4

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Comments

Sinisa Hajnal 11-Aug-15 2:21am

Put the initializing code in a constructor. Or some initialize method. Define SqlConnection _conn = null; and set it in the method. You don't need connection string at class level. You could also define const string connectionString = ... and use it throughout the class.

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OriginalGriff · Accepted Answer · 2015-08-10T20:19:00

If you get an error message you don't understand, copy and paste it into Google - the chances are very good that someone else has met this before.
In your case loads of people have been confused by this one!
"A field initializer cannot reference the non-static field"[^]

If you have a look at the links, it explains the problem - you can't declare and set a class-level variable to a non-static value.

con is not inside a method, so it can't access non-static information in an initialiser (because it all has to be done before the class constructor is called)
Move the initialization into your class constructor, and you'll be fine:

C#

public class MyFunctions
    {
        string connstring = ConfigurationManager.ConnectionStrings["EpfConnectionString"].ConnectionString;
        SqlConnection con = null;
        public MyFunctions()
        {
            con = new SqlConnection(connstring);
        }
    }

Arasappan · Accepted Answer · 2015-08-10T20:29:00

Solution 2

C#

SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["EpfConnectionString"].ConnectionString);

Posted 10-Aug-15 20:29pm

Arasappan

Comments

harshil gandhi 11-Aug-15 3:14am

Many thanks...@Arasappan