using System;

using System.IO;                    

​

public class Program

{

    public static void Main()

    {

        var testString = "ÃÄÀÁÅÆÇÈÉÊËÌÍÎÏ";

        var testString2 = "M=G!T-CS#D(A)E1%2+2.3~Y_QW";

        var testString3 = "測試鍵號";

        var result = "";

        char[] invalidFileChars = Path.GetInvalidFileNameChars();

        foreach (char s in invalidFileChars)

        {

            testString = testString.Replace(s, '-');

        }

        foreach (char s in invalidFileChars)

        {

            testString2 = testString2.Replace(s, '-');

        }

        foreach (char s in invalidFileChars)

        {

            testString3 = testString3.Replace(s, '-');

        }

        Console.WriteLine(testString);

        Console.WriteLine(testString2);

        Console.WriteLine(testString3);

    }

}