private static void OpenSqlConnection()
{
    string connectionString = GetConnectionString();

    using (SqlConnection connection = new SqlConnection())
    {
        connection.ConnectionString = connectionString;
        connection.Open();

       
    }
}

static private string GetConnectionString()
{
    // To avoid storing the connection string in your code, 
    // you can retrieve it from a configuration file.
    return "Data Source=MSSQL1;Initial Catalog=AdventureWorks;"
        + "Integrated Security=true;";
}

private static void UpdateDemographics(Int32 customerID,
    string demoXml, string connectionString)
{
    // Update the demographics for a store, which is stored 
    // in an xml column. 
    string commandText = "StoredProcedureName";

    using (SqlConnection connection = new SqlConnection(connectionString))
    {
        SqlCommand command = new SqlCommand(commandText, connection);

        command.Parameters.Add("@ID", SqlDbType.Int);
        command.Parameters["@ID"].Value = customerID;
        command.CommandType = CommandTypes.StoredProcedure;
        // Use AddWithValue to assign Demographics.
        // SQL Server will implicitly convert strings into XML.
        command.Parameters.AddWithValue("@demographics", demoXml);

        try
        {
            connection.Open();
            Int32 rowsAffected = command.ExecuteNonQuery();
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
        }
    }
}