using System;

using System.Globalization;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

​

string[] a = new string[] { "1.250.365,45", "500,56", "500,000,000", "5000", "1.2", "120.12", "120,123.89", "1,789,365.90", "0,2" };

var b = new List<decimal>();

​

foreach (var item in a)

{

    var temp = item;

    var decimalSeparator = "";

    var separators = ".,";

    var j = 0;

​

    for (var i = item.Length - 2; i > 0 && j < 2; i--, j++)

    {

        if (item[i] == ',' || item[i] == '.')

        {

            decimalSeparator = item[i].ToString();

            break;

        }

    }

​

    NumberFormatInfo nfi = new NumberFormatInfo();

    if (decimalSeparator.Length > 0)

    {

        nfi.NumberDecimalSeparator = decimalSeparator;

        separators = separators.Replace(decimalSeparator, "");

        temp = temp.Replace(separators, "");

    }

​

    decimal.TryParse(temp, NumberStyles.Currency, nfi, out decimal bb);

    b.Add(bb);

}

​

Console.WriteLine(string.Join(" | ", b.ToArray()));

Console.ReadLine();

    }

}