从SQL Server数据库中选择C#

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

class Program
{
    static void Main()
    {
        string connectionString = "Server=your_server;Database=your_database;User Id=your_username;Password=your_password;";
        
        using (SqlConnection connection = new SqlConnection(connectionString))
        {
            try
            {
                connection.Open();
                string query = "SELECT * FROM YourTable";
                SqlCommand command = new SqlCommand(query, connection);
                
                using (SqlDataReader reader = command.ExecuteReader())
                {
                    while (reader.Read())
                    {
                        Console.WriteLine(reader["ColumnName"].ToString());
                    }
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine("An error occurred: " + ex.Message);
            }
        }
    }
}