C#如何实现返回SQL结果列表的方法？

Question

using (var connection = new SqlConnection("user id=xxx;" +
                   "password=xxx;server=xxx;" +
                   "Trusted_Connection=yes;" +
                   "database=xxx; " +
                   "connection timeout=30"))
{
    connection.Open();
    string sql = "SELECT * FROM testTable";
    using (var command = new SqlCommand(sql, connection))
    {
        using (var reader = command.ExecuteReader())
        {
            while (reader.Read())
            {
                .
                .
                .
                .
                .
            } 
        }
    }
}

上面的代码可用于检索记录行列表并在我的C#控制台应用程序中显示它们,但在Main方法中会非常混乱.我想知道如何处理这些记录并通过调用方法将它们存储到列表或其他内容中.是否可以在C#控制台应用程序中使用？

Answer 1

不知道数据库表中的内容,我将编写一个示例:

帐户类:

public class Person
{
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public int Age { get; set; }
}

现在你可以让你的reader循环填充每个Person,如下所示:

while (reader.Read())
{
    var person = new Person();
    person.FirstName = reader["FirstName"].ToString();
    person.LastName = reader["LastName"].ToString();
    person.Age = Convert.ToInt32(reader["Age"]);
}

最后,我们要构建一个Person要返回的对象列表,如下所示:

var listOfPerson = new List<Person>();

while (reader.Read())
{
    var person = new Person();
    person.FirstName = reader["FirstName"].ToString();
    person.LastName = reader["LastName"].ToString();
    person.Age = Convert.ToInt32(reader["Age"]);

    listOfPerson.Add(person);
}

return listOfPerson;

完整代码:

public List<Person> LoadPeople()
{
    var listOfPerson = new List<Person>();

    using (var connection = new SqlConnection("user id=xxx;" +
               "password=xxx;server=xxx;" +
               "Trusted_Connection=yes;" +
               "database=xxx; " +
               "connection timeout=30"))
    {
        connection.Open();
        string sql = "SELECT * FROM testTable";
        using (var command = new SqlCommand(sql, connection))
        {
            using (var reader = command.ExecuteReader())
            {
                while (reader.Read())
                {
                    var person = new Person();
                    person.FirstName = reader["FirstName"].ToString();
                    person.LastName = reader["LastName"].ToString();
                    person.Age = Convert.ToInt32(reader["Age"]);

                    listOfPerson.Add(person);
                }
            }
        }
    }

    return listOfPerson;
}