using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

​

//Can be class, record, struct, etc.

public record MyObj_3Properties(string Prop1, string Prop2, string Prop3);

public record MyObj_4Properties(string Prop1, string Prop2, string Prop3, string Prop4);

​

public class Program

{

    public static void Main()

    {

​

        //Object (class, record, etc.) w/3 string properties

        var list_3Properties = new List<MyObj_3Properties> {

            new MyObj_3Properties("A1", "B1", "C1"),

            new MyObj_3Properties("A1", "B2", "C2"),

            new MyObj_3Properties("A3", "B3", "C3")

        };

​

        Console.WriteLine("Object w/3 Properties");

        Console.WriteLine(list_3Properties.Join(colSeparator: ',', rowSeparator: '\n'));

​

        //Object (class, record, etc.) w/3 string properties

        var list_4Properties = new List<MyObj_4Properties> {

            new MyObj_4Properties("A1", "B1", "C1", "D1"),

            new MyObj_4Properties("A1", "B2", "C2", "D2"),

            new MyObj_4Properties("A3", "B3", "C3", "D3")

        };

​

        Console.WriteLine("\nObject w/4 Properties");

        Console.WriteLine(list_4Properties.Join(colSeparator: ',', rowSeparator: '\n'));

    }

}

​

public static class EnumerableStringJoinExtension

{

    public static string Join<T>(this IEnumerable<T> values, char colSeparator, char? rowSeparator = null)

    {

        var strProperties = typeof(T).GetProperties().Where(r => r.PropertyType == typeof(string));

        var sb = new StringBuilder();

        foreach (var val in values)

            sb.Append(string.Join(colSeparator, strProperties.Select(r => r.GetValue(val)))).Append(rowSeparator ?? colSeparator);

        sb.Remove(sb.Length - 1, 1);

        return sb.ToString();

    }

}

​