How to Export CSV without using any Package in C# (,NET Core)?

Question

How can you create a well structured csv file without using any packages in .NET core.

And use class Keys as Header.

    public class TestArray
    {
        public string LastName{ get; set; }
        public string FirstName { get; set; }
        public string Age { get; set; }
        public string MoNumber { get; set; }
    }

I tried with the CsvHelper Package, it's work Perfectly, but I want to Export csv file without using any packages.

Answer 1

public class TestArray
{
    public string LastName { get; set; }
    public string FirstName { get; set; }
    public string Age { get; set; }
    public string MoNumber { get; set; } 
}

public static void ExportCsv<TestArray>(List<TestArray> genericList, string filePath)
{
    var sb = new StringBuilder();
    var header = "";
    var info = typeof(TestArray).GetProperties();
    if (!File.Exists(filePath))
    {
        var file = File.Create(filePath);
        file.Close();
        foreach (var prop in typeof(TestArray).GetProperties())
        {
            header += prop.Name + ",";
        }
        header = header.Substring(0, header.Length - 2);
        sb.AppendLine(header);
        TextWriter sw = new StreamWriter(filePath, true);
        sw.Write(sb.ToString());
        sw.Close();
    }
    foreach (var obj in genericList)
    {
        sb = new StringBuilder();
        var line = "";
        foreach (var prop in info)
        {
            line += prop.GetValue(obj, null) + ",";
        }
        line = line.Substring(0, line.Length - 2);
        sb.AppendLine(line);
        TextWriter sw = new StreamWriter(filePath, true);
        sw.Write(sb.ToString());
        sw.Close();
    }
}

Usage:

    var arrayData = new List<TestArray>
                    {
                        new() {
                            LastName = "John", FirstName = "Deo", Age = "20", MoNumber = "123456789"
                        },
                        new() {
                            LastName = "Seno", FirstName = "Verma", Age = "10", MoNumber = "9876543210"
                        }
                    };

    string filePath = "E:\\FolderName\\fileName.csv";  // file path should be include file Name and extention

    ExportCsv(arrayData, filePath);

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