ExecuteReader 获取数据集的基础使用

/// <summary>
/// 获取多个结果集
/// </summary>
/// <param name="sql"></param>
/// <returns></returns>
/// <exception cref="Exception"></exception>
public static SqlDataReader GetReader(string sql, params SqlParameter[] parse)
{
    SqlConnection conn = new SqlConnection(connStr);
    SqlCommand cmd = new SqlCommand(sql, conn);
    try
    {
        conn.Open();
        cmd.Parameters.Clear();
        cmd.Parameters.AddRange(parse);
        return cmd.ExecuteReader(CommandBehavior.CloseConnection);
    }catch (Exception ex)
    {
        conn.Close();
        throw new Exception(ex.Message);
    }
}

//获取班级列表
/// <summary>
/// StudentClass 这是我定义的实体类
/// SqlHelper.GetReader() 方法是我定义的 SqlHelper数据库访问类
/// </summary>
/// <returns></returns>
public List<StudentClass> GetStudentClasses()
{
    string sql = "select * from StudentClass";
    List<StudentClass> students = new List<StudentClass>();
    SqlDataReader sqlData = SqlHelper.GetReader(sql);
    if (sqlData.Read())
    {
        students.Add(new StudentClass()
        {
            ClassId = Convert.ToInt32(sqlData["ClassId"]),
            ClassName = sqlData["ClassName"].ToString()
        }) ;
    }
    return students ;
}

public class StudentClass
{
    public int ClassId { get; set; }
    public string ClassName { get; set; }
}