问循环遍历数组，在每次迭代时取一个子集并存储到对象列表中。

EN

line #0 - group #0 
line #1 - group #0 
...
line #6 - group #0
line #7 - group #1
...
line #13 - group #1
line #14 - group #2
...

   using System.IO; 
   using System.Linq;
   ...

   public static List<Settlement> ReadFromLogFile() {
     string filename = Path.Combine(path, @"BM_DB_MIGRATION.txt");

     if (File.Exists(filename)) {
       return File
         .ReadLines(filename)
         .Select((line, index) => new {
            line,
            index
          }) 
         .GroupBy(item => item.index / 7, // group of [0..6] lines, then [7..13] lines etc. 
                  item => item.line)
         .Select(group => group.ToArray()) // Let's optimize group items access
         .Select(group => new Settlement( // turn 7 lines into Settlement
            //TODO: put the right Settlement constructor's syntax here
            group.ElementAtOrDefault(0),  // ...OrDefault - null, if line doesn't exist  
            group.ElementAtOrDefault(1),
            group.ElementAtOrDefault(2), 
            group.ElementAtOrDefault(3),  
            group.ElementAtOrDefault(4),
            group.ElementAtOrDefault(5), 
            group.ElementAtOrDefault(6)  
          ))
         .ToList();  
     }

     return new List<Settlement>(); 
   }

public static List<Settlement> ReadFromLogFile()
{
    string filename = path + @"\BM_DB_MIGRATION.txt";
    List<Settlement> settlements = new List<Settlement>();

    if (File.Exists(filename))
    {
        string[] lines = File.ReadAllLines(filename);

        // Reading 7 elements from lines into an object of Settelment at each iteration 
        // and store the object in a list of objects...
        var record = new List<string>(7);
        foreach (var line in lines)
        {
            if (record.Count == 7)
            {
                // convert the lines to the Settlement data structure
                var s = new Settlement(record);
                settlements.Add(s);
                record.Clear();
            }

            record.Add(line);
        }
    }

    return settlements;
}

public static List<Settlement> ReadFromLogFile()
{
    string filename = path + @"\BM_DB_MIGRATION.txt";
    List<Settlement> settlements = new List<Settlement>();

    if (File.Exists(filename))
    {
        string[] lines = File.ReadAllLines(filename);

        // Reading 7 elements from lines into an object of Settelment at each iteration 
        // and store the object in a list of objects...

        for(int i = 0; i < lines.length; i += 7)
        {
            var obj = lines.Skip(i).Take(7).ToArray();
            var settlement = new Settlement(obj);

            settlements.Add(settlement);
        }
    }

    return settlements;
}