C# MSSQL Simple example Read data

using System;
using System.Data;
using System.Data.SqlClient;


class Program
{
    static void Main()
    {
        string str = "Data Source=(local);Initial Catalog=Northwind;"
            + "Integrated Security=SSPI";
        ReadOrderData(str);
    }

    private static void ReadOrderData(string connectionString)
    {
        string queryString =
            "SELECT OrderID, CustomerID FROM dbo.Orders;";

        using (SqlConnection connection =
                   new SqlConnection(connectionString))
        {
            SqlCommand command =
                new SqlCommand(queryString, connection);
            connection.Open();

            SqlDataReader reader = command.ExecuteReader();

            // Call Read before accessing data. 
            while (reader.Read())
            {
                ReadSingleRow((IDataRecord)reader);
            }

            // Call Close when done reading.
            reader.Close();
        }
    }

    private static void ReadSingleRow(IDataRecord record)
    {
        Console.WriteLine(String.Format("{0}, {1}", record[0], record[1]));
    }

}

SQL Compact connection string "Data Source=C:\userDB.sdf;Password=password;Persist Security Info=True"

In thos case dont forget to use CE components, for example System.Data.SqlServerCe.SqlCeConnection

101 Пример использования LINQ

Нашел ссылку, очень много полезных примеров применения LINQ http://code.msdn.microsoft.com/101-LINQ-Samples-3fb9811b

с# Serialization to file or string / с# Сериализация в файл или в строку + Десериализация

static void SerializeToFile(object o)
{
  XmlSerializer serializer = new XmlSerializer(o.GetType());
  using (Stream writer = new FileStream("output.xml", FileMode.Create))
  {
    serializer.Serialize(writer, o);
  }
}

public static string SerializeToString(object obj)
        {
            XmlSerializer serializer = new XmlSerializer(obj.GetType());

            using (StringWriter writer = new StringWriter())
            {
                serializer.Serialize(writer, obj);

                return writer.ToString();
            }
        }
public static object DeserializeFromFile(object obj,string path)
{
  XmlSerializer serializer = new XmlSerializer(obj.GetType());
 
  using (XmlReader reader = XmlReader.Create(path))
  {
    object o = serializer.Deserialize(reader);
  }
}

//From string

var serializer = new XmlSerializer(typeof(Car));
using (var reader = new StringReader(xml))
{
    var car = (Car)serializer.Deserialize(reader);
}

Изменить строку подключения в app.conig / How to change connection string in app.config

static void AddConnectionStringMyDB()
        {
            System.Configuration.Configuration config =
                ConfigurationManager.OpenExeConfiguration(
                ConfigurationUserLevel.None);
            ConnectionStringsSection csSection =
              config.ConnectionStrings;
            ConnectionStringSettings connection = new ConnectionStringSettings();
            connection.Name = "Rozn_Client.Properties.Settings.userDBConnectionString";
            connection.ProviderName = "Microsoft.SqlServerCe.Client.4.0";
            connection.ConnectionString = "Data Source=|DataDirectory|\\myDB.sdf;Password=mypassword;Persist Security Info=True";
            csSection.ConnectionStrings.Add(connection);
            config.Save(ConfigurationSaveMode.Modified);
            ConfigurationManager.RefreshSection("connectionStrings");
        }