Add and handle connection strings in an application configuration file: Part I

Figure 3

• Configure your connection as you like
• Save the settings by right clicking the first tab and choosing save file

Figure 4

Add the connection string into the application configuration file directly:

The configuration file is located at the same directory as the application one with ".exe.config" as extension and as icon.

• Open it and add directly whatever your want in terms of connection strings, the "intellisense" will help you to do that.

After adding a couple of connections strings the configuration file looks like bellow:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<configSections>
</configSections>
<connectionStrings>
<add name="Connection1" connectionString="Data Source = STANDARD;Initial Catalog = Northwind; Integrated Security = true "/>
<add name="Connection2" connectionString="Provider = Microsoft.Jet.OLEDB.4.0;Data Source = C:\Test.mdb" />
</connectionStrings>
</configuration>

In this case, two connections string are added. The first one connects the application to the Northwind SQL Server 2005 database, and the second connects it to an Access database called Test in the drive directory C:\.

Add a connection string programmatically:

To add a new connection string programmatically, do as follow:

• Add this method to your code.
  
  

  private void AddNewConnectionString()

  {

  /* This code provides access to configuration files using OpenMappedExeConfiguration,method. You can use the OpenExeConfiguration method instead. For further informatons,consult the MSDN, it gives you more inforamtions about config files access methods*/

  ExeConfigurationFileMap oConfigFile = new ExeConfigurationFileMap();

  oConfigFile.ExeConfigFilename = Application.StartupPath + "\\AppConfig.exe.config[1]";

  Configuration oConfiguration = ConfigurationManager.OpenMappedExeConfiguration(oConfigFile,ConfigurationUserLevel. None);

  //Define a connection string settings incuding the name and the connection string

  ConnectionStringSettings oConnectionSettings = new ConnectionStringSettings("oConnection", "DataSource=STANDARD;Initial Catalog=Northwind; Integrated Security=true");

  //Adding the connection string to the oConfiguration object

  oConfiguration.ConnectionStrings.ConnectionStrings.Add(oConnectionSettings);

  //Save the new connection string settings

  oConfiguration.Save(ConfigurationSaveMode.Full);

  MessageBox.Show(string.Format("Connection {0} is added",oConnectionSettings.Name));

  //Restart the application to be sure that connection is restored in the config file

  Application.Restart();

  }
  
  

• Call the method at the run time and open the configuration file. The result will be:
  

  <?xml version="1.0" encoding="utf-8" ?>

  <configuration>

  <configSections>

  </configSections>

  <connectionStrings>

  <add name="oConnection"

  connectionString="Data Source=STANDARD; Initial Catalog=Northwind; Integrated Security=true" />

  </connectionStrings>

  </configuration>

Retrieve the connection string parameters for use purposes

Information about connection strings can be retrieved from the configuration file programmatically. Just add this method to the code:

private static void RetrieveInfo()

{

/* This code provides access to configuration files using OpenMappedExeConfiguration,method. You can use the OpenExeConfiguration method instead. For further informatons, consult the MSDN, it gives you more inforamtions about config files access methods*/

ExeConfigurationFileMap oConfigFile = new ExeConfigurationFileMap();

oConfigFile.ExeConfigFilename = Application.StartupPath + \\AppConfig.exe.config;

Configuration oConfiguration = ConfigurationManager.OpenMappedExeConfiguration(oConfigFile, ConfigurationUserLevel.None);

//Define the name of the connection

string oName = oConfiguration.ConnectionStrings.ConnectionStrings["oConnection"].Name;

//Define the connection string of the connection

string oConnectionString = oConfiguration.ConnectionStrings.ConnectionStrings["oConnection"].ConnectionString;

//Show the parameters

MessageBox.Show(string.Format("The connection name is :", oName));

MessageBox.Show(string.Format("The connection connection string :", oConnectionString));
}

Part II