How to read text file using LINQ and covert it into C# class object properties

One of the common problems with "quick and easy" solutions with regards to comma delimited files is the fact that eventually you will run across a csv that has double quote text qualifiers. So for this end, I always recommend TextFieldParser.

using Microsoft.VisualBasic.FileIO;

void Main()
{
	string strReadFile = @"D:\Country.txt";
	List<CountryList> lst = ParseCountryList(strReadFile, ",", true);
}

class CountryList
{
	public string ID { get; set; }
	public string NAME { get; set; }
}

static List<CountryList> ParseCountryList(string FileName, string Delimiter, bool IsQualified)
{
	var result = new List<CountryList>();
	using (var tfp = new TextFieldParser(FileName) {
		Delimiters = new string[] { Delimiter },
		HasFieldsEnclosedInQuotes = IsQualified
	})
	{
		while (!tfp.EndOfData)
		{
			var fields = tfp.ReadFields();
			if (fields.Length >= 2)
			{
				var cl = new CountryList
				{
					ID = fields[0].Trim(),
					NAME = fields[1].Trim()
				};
				result.Add(cl);
			}
		}
	}
	return result;
}

AFell raises good points about CSV file potential issues.
I'm going to assume that for now you know that the file format never has an ID value that's quoted including a comma.
At a minimum this should give you a starting point for something more sophisticated if necessary.

// You don't need to read all of the lines into an array, just read 'em as you go
char [] delimiters = new char[] { ',' };
var fileLines = File.ReadLines(strReadFile)
                    .Skip(startLine)
                    // .Take(..) is necessary ONLY if you DON'T want to read to the end
                    // in your question you said "from Line number 4 to end"
                    // .Take(lineCount)
                    .Select(line => {
                       string[] ss = line.Split(delimiters, 2);
                       return (ss.Length == 2)
                              ? new CountryList() { ID = ss[0], NAME = ss[1] }
                              : null;              // null for ill-formatted line
                     })
                    .Where(x => x != null)      // filter to good lines
                    .ToList();

(I didn't test this... There may be a typo or two...)