C#

private _myClass;
public void SetupDomain(string configFile, string domainName)
{
  AppDomainSetup setup = new AppDomainSetup();
  setup.ConfigurationFile = configFile;
  AppDomain domain = AppDomain.CreateDomain(domainName, null, setup);

  _myClass = (MyDllClass)domain.CreateInstanceAndUnwrap("MyDll", "MyDll.MyDllClass");
}

 SetupDomain("MyDll.Dll.Config", "My domain");
int value = _myClass.GetConfigItem();

public class MyLibClass
{
	private string m_configName = "MyLib.dll.config";
	private string keyName = "APP_CONFIG_FILE";

	public MyLibClass()
	{
		Reload();
	}

	public void Reload()
	{
		// build the path to the config file
		string configPath = System.IO.Path.Combine(Environment.CurrentDirectory, m_configName);

		// get the name of the hosting application's config file (so we can reset it later)
		string appConfigFile = AppDomain.CurrentDomain.GetData(keyName).ToString();

		// plug in the DLL's config file path/name
		AppDomain.CurrentDomain.SetData(keyName, configPath);

		// load some app settings using the ConfigurationManager class
		string xyz = ConfigurationManager.AppSettings["mySetting"];

		// reset the current config file to the hosting app's config file
		AppDomain.CurrentDomain.SetData(keyName, appConfigFile);
	}
}

[System.Runtime.InteropServices.DllImport ( "Winmm" , SetLastError=true , EntryPoint="PlaySound" )]
private static extern bool
API_PlaySound
(
    string        pszSound
,
    System.IntPtr hmod
,
    uint          fdwSound
) ;

<br />
//Removes currently selected node, or root if nothing is selected.<br />
treeview.Nodes.Remove(treeView.SelectedNode);

using Microsoft.SqlServer.Management.Smo;<br />
private static Server srvSql;<br />
private static ServerConnection srvConn;<br />

<br />
 servername = cmbServer.Text;<br />
                     srvConn = new ServerConnection(cmbServer.SelectedItem.ToString());<br />
                                        srvConn.LoginSecure = true;<br />
                   <br />
                    srvSql = new Server(srvConn);<br />

        void Restoring_data()<br />
        {<br />
<br />
            // If there was a SQL connection created<br />
            if (srvSql != null)<br />
            {<br />
                // If the user has chosen the file from which he wants the database to be restored<br />
<br />
                // Create a new database restore operation<br />
                Restore rstDatabase = new Restore();<br />
                // Set the restore type to a database restore<br />
                rstDatabase.Action = RestoreActionType.Database;<br />
                // Set the database that we want to perform the restore on<br />
                rstDatabase.Database = "DataBaseName"<br />
                // Set the backup device from which we want to restore, to a file<br />
                BackupDeviceItem bkpDevice = new BackupDeviceItem(txtbackup.Text.ToString(), DeviceType.File);<br />
                // Add the backup device to the restore type<br />
                rstDatabase.Devices.Add(bkpDevice);<br />
                // If the database already exists, replace it<br />
                rstDatabase.ReplaceDatabase = true;<br />
<br />
                // Perform the restore<br />
                rstDatabase.SqlRestore(srvSql);<br />
<br />
            }<br />
            else<br />
            {<br />
                // There was no connection established; probably the Connect button was not clicked<br />
                MessageBox.Show("A connection to a SQL server was not established.", "Not Connected to Server", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);<br />
            }