Connect database through config file

Question

Hi I want to connect database through configaration file. I am getting error. Here is my code: Configuration file: My code in c# is: string connStr = ConfigurationManager.ConnectionStrings[databaseconnectionstring].ConnectionString; SqlConnection con = new SqlConnection(connStr); con.open(); Thanks Darma

Vulpes · Answer

The previous error was a C# compiler error but if you're getting a runtime error on con.Open() then that's a connection error - perhaps something wrong with your connection string the connection is already open or similar. Try changing the code to this so we can see what the error is: private void button1_Click(object sender EventArgs e) { try { con.Open(); MessageBox.Show(Connection is established); } catch(Exception ex) { MessageBox.Show(ex.Message); } }

Vulpes · Answer

In a C# string the backslash character '\' is used to 'escape' some other characters. For example: 
 - new line  - carriage return 	 - tab \b - backspace Consequently when you really need a backslash you have to double it like you've done when passing a string to you SqlConnection constructor. This doesn't apply to configuration files which are just XML files. So if you double the backslash in the configuration file then it won't work properly.

darma teja · Answer

Hi Vulpes You are 100% right. There is a mistake in my connection string. I have a doubt in this: When i put connection string without configuration file for example: like below code It is working. SqlConnection con = new SqlConnection(Data Source=DARMATEJA-PC\MSSQLSERVER2;Initial Catalog=database1.DB;Integrated Security=True); The same string when i use it in Configuration file it is giving me error. Now i removed \ from the string than it is working. It means the following connection string i wrote in config file. Data Source=DARMATEJA-PC\MSSQLSERVER2;Initial Catalog=database1.DB;Integrated Security=True What happens when i remove one \? Darma

darma teja · Answer

Hi Vulpes I tried with your code. Even i am getting error exactly at con.open(); I really tried hard for 2 days. I can not connect through configuration. I want to open connection in different methods. Thats why i want create a connection in the class. So that i can open database connection in different methods. Thanks allot!! Darma

Vulpes · Answer

Try it like this: namespace Databaseconfig { public partial class Form1 : Form { string strConnString; SqlConnection con; public Form1() { InitializeComponent(); strConnString = ConfigurationManager.ConnectionStrings[ databaseconnection].ConnectionString; con = new SqlConnection(strConnString); } private void button1_Click(object sender EventArgs e) { con.Open(); MessageBox.Show(Connection is established); } } }

darma teja · Answer

Hi Satyapriya Thanks allot. I am developing a desktop application. I want put database connection string in configuration file. Could you please tell me where i am getting error: here is my code: using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using System.Data.SqlClient; using System.Configuration; namespace Databaseconfig { public partial class Form1 : Form { string strConnString = ConfigurationManager.ConnectionStrings[ databaseconnection ].ConnectionString; SqlConnection con = new SqlConnection(strConnString); public Form1() { InitializeComponent(); } private void button1_Click(object sender EventArgs e) { con.Open(); MessageBox.Show(Connection is established); } } } ****************************** My configuration file is: connectionString=connection string providerName=System.Data.SqlClient/> Thanks Darma

Satyapriya Nayak · Answer

Hi Darma Call it in webpage as string strConnString = ConfigurationManager.ConnectionStrings[dbconnection].ConnectionString; SqlConnection con = new SqlConnection(strConnString); Thanks If this post helps you mark it as answer

darma teja · Answer

I am getting following error: A field initializer cannot reference the non-static field method or property. i am getting error exactly at this line: SqlConnection con = new SqlConnection(connStr); Darma

Vilas Gite · Answer

hi Darma please refer: http://www.dreamincode.net/forums/topic/111383-how-to-connect-the-sql-database-using-application-config-file/ T hanks

Shen Hengbin · Answer

You should show your error message first.