c程序错误，括号错位

我在第50行第13列得到一个错误，"命名空间不能直接包含字段或方法等成员"还有第47行第17列"预期catch或finally"代码将是控制台模式下的C#程序，使用C#System.IO库将数据文件作为顺序文件加载到ArrayList数据结构中（使用System.Collection库）。将文件中的每一行存储为单独的记录。然后将文件加载到ArrayList中，根据LastName字段按升序对数据进行排序，并显示以下字段：接下来，根据ZIP字段按降序对数据进行排列，并显示下列字段：最后显示状态为"NY"的每个人的所有记录（及其所有字段）

using System;
using System.IO;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ConsoleApplication24
{
class dataItem
{
    // this class will hold the data from one string in the file
    string FirstName;
    string LastName;
    // etc.
}
class Program
{
    static void Main(string[] args)
    {
        // create a place to store our data
        ArrayList data = new ArrayList();
        // open and read a text file
        StreamReader sr = new StreamReader("Unit4IP");
        try
        {
            using (StreamReader sr = new StreamReader("Unit4IP"))
            {
                // need a string to hold the fields and a string variable for each line of text.
                String line;
                string[] fields;
                while ((line = sr.ReadLine()) != null);
                }
                    fields = line.Split(new Char [] {','});
                    Console.WriteLine(fields[0]);
                    Console.WriteLine(fields[1]);
            // from here you can create a data to store your fields in it
            // then insert the object into your data ArrayList.
            // after that, you can do the sorting and output after this loop is done reading
                }
            }
        }
        catch (Exception e)
        {
            Console.WriteLine("The file could not be read:");
            Console.WriteLine(e.Message);
        // Store text file contents in an appropriate data structure
        // Sort data
        // Output data
        // put this at the end to keep the console window from disappearing
            Console.WriteLine("Press enter to continue..");
            Console.ReadLine();
    }
}

while ((line = sr.ReadLine()) != null);
                }