public static class ConnectionString
    {
        private static string strConnSrting;
        static ConnectionString()
        {
            //strConnSrting = ConfigurationManager.ConnectionStrings["dbSkladConnectionString"].ConnectionString;
        //    Console.WriteLine(strConnSrting);
            strConnSrting = @"Data Source=GENAXVM\GENAX;" +
            "Initial Catalog = dbSklad;" +
            "Persist Security Info=True;" +
            "User ID=admin;" +
            "Password=adminadmin;" +
            "Network Library=dbmssocn";
        //    Console.WriteLine(strConnSrting);
        }
        public static string getConnectionString
        {
            get { return strConnSrting; }
        }
    }

strConnSrting = ConfigurationManager.ConnectionStrings["dbSkladConnectionString"].ConnectionString;

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <connectionStrings>
    <add name="dbSkladConnectionString"
      connectionString="Data Source=GENAXVM\GENAX;Initial Catalog = dbSklad;Persist Security Info=True;User ID=admin;Password=adminadmin;Network Library=dbmssocn"
      providerName="System.Data.SqlClient" />
  </connectionStrings>
</configuration>