Declaring connection string in a class

are you able to get the data. if not then share your web.confg

in which line you are getting error.

Now throwing exception ..


"Object reference not set to an instance of an object."}


using System.Data.SqlClient;
using System;
using System.Data;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Configuration;
namespace CSharpTutorial
{
        public class MyFunctClass
             
    {

Here----->>>if I use Static         
 //static string connstr = ConfigurationManager.ConnectionStrings["myConnectionString"].ConnectionString;
           //static string connstr = ConfigurationManager.ConnectionStrings["myConnectionString"].ToString();
            string connstr = ConfigurationManager.ConnectionStrings["myConnectionString"].ToString();


           public SqlConnection cn;
           public MyFunctClass()
           {


               cn = new SqlConnection(connstr);


           }
           //SqlConnection cn = new SqlConnection(connstr);
         
            SqlCommand cmd= new SqlCommand();
            SqlDataReader dr;




            public DataTable readData(int id)
            {
                cmd.Connection = cn;
                cmd.CommandText = "Select * From testClass1 Where ID='"+ id +"'";
                cn.Open();
                dr = cmd.ExecuteReader();
                DataTable dt = new DataTable("testClass1");
                dt.Load(dr);
                return dt;
            }




    }
}

----------------------------------
        protected void btnSearch_Click(object sender, EventArgs e)
        {
         
Here if I dont use static....>>>

 MyFunctClass a = new MyFunctClass();
           DataTable dtn = a.readData(Convert.ToInt32(tbSearch2.Text));
            tbUser.Text = dtn.Rows[0]["UserName"].ToString();
            tbId.Text = dtn.Rows[0]["ID"].ToString();
            tbDesig.Text = dtn.Rows[0]["Desig"].ToString();
        }

try like this:


protected void btnSearch_Click(object sender, EventArgs e)
        {
           MyFunctClass a = new MyFunctClass();
           DataTable dtn = a.readData(Convert.ToInt32(tbSearch2.Text));
            tbUser.Text = dtn.Rows[0]["UserName"].ToString();
            tbId.Text = dtn.Rows[0]["ID"].ToString();
            tbDesig.Text = dtn.Rows[0]["Desig"].ToString();

        }

Yes, here in class

have you declare readData()

Hi,
   Even If I do that way..showing same error..Non Invocable member

string connStr = ConfigurationManager.ConnectionStrings["myConnectionString"].ToString();

or

string connstr = ConfigurationManager.ConnectionStrings["myConnectionString"].connectionString;



what is the difference between these two

Hey...showing same error for this stuff...Non invocable Member

you should use connection in constructor, static is not good way to declare it

public class MyFunctClass
    {
        string connstr = ConfigurationManager.ConnectionStrings["myConnectionString"].ToString();
        public SqlConnection cn;
        public MyFunctClass()
        {
            cn = new SqlConnection(connstr);
        }
    }

try this:

using System.Data.SqlClient;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Configuration;
namespace CSharpTutorial
{
        public class MyFunctClass
             
    {
           static string connstr = ConfigurationManager.ConnectionStrings["myConnectionString"].ToString();
    SqlConnection cn = new SqlConnection(connstr);

  
    }
}

try like this

public class MyFunctClass
    {
        string connstr = ConfigurationManager.ConnectionStrings["myConnectionString"].ToString();
        public SqlConnection cn;
        public MyFunctClass()
        {
            cn = new SqlConnection(connstr);
        }
    }

field initializer cannot reference the nonstatic field,



even if do like this same error
public Static SqlConnection cn = new SqlConnection(connstr);

Hi,
  When I am passing this connection string to sqlconnection object showing an error...

use the below link for converting VB.NET to C#

http://www.developerfusion.com/tools/convert/vb-to-csharp/

Regards,
Iftikar

Hi,
        Try like this


Regards,
Iftikar

try this:


 
string connStr = ConfigurationManager.ConnectionStrings["myConnectionString"].ToString();

or

 string connstr = ConfigurationManager.ConnectionStrings["myConnectionString"].connectionString;