Get Connection String from Web.config in asp.net

Question

I want to know the ways to get connection string from web.config file in asp.net.

I just only know the below way .

using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Configuration;      namespace Sherserve.DataAccessLayer     {         public class DBGateway         {             public static string conString;              public DBGateway()             {                 conString = ConfigurationManager.ConnectionStrings["test"].ToString();             }         }     } 

Answer 1

Using the ConfigurationManager.ConnectionStrings is about the only proper way, to use it properly with sanity check you can have such code:

public DBGateway() {     ConnectionStringSettings mySetting = ConfigurationManager.ConnectionStrings["test"];     if (mySetting == null || string.IsNullOrEmpty(mySetting.ConnectionString))         throw new Exception("Fatal error: missing connecting string in web.config file");     conString = mySetting.ConnectionString; } 

This will throw useful error in case the connection string is missing, instead of cryptic "null object" error.

Worth to mention that the ConnectionStringSettings class is overriding the ToString() method:

public override string ToString() {     return this.ConnectionString; } 

So it means that using ConfigurationManager.ConnectionStrings["test"].ToString() is the same like ConfigurationManager.ConnectionStrings["test"].ConnectionString however you still better perform sanity check and personally it looks cleaner to use the actual property and not depend on the class to give it.

Answer 2

Here is the whole solution:-

string constring = System.Configuration.ConfigurationManager.ConnectionStrings["ConnectionStringName"].ConnectionString; SqlConnection con = new SqlConnection(constring); DataSet ds = new DataSet(); try  {    SqlDataAdapter dataAdapter = new SqlDataAdapter(query, con);    SqlCommandBuilder commandBuilder = new SqlCommandBuilder(dataAdapter);    con.Open();    dataAdapter.Fill(ds, "table");    return ds;  }  catch (Exception ex)   {   }     finally     {         if (con.State == System.Data.ConnectionState.Open)             con.Close();     } 

This is how you can fetch records from database into datatable.

Hope this is what you were looking for.