Opening mp3 by not-default program C sharp

Question

How can I open mp3 file with RealPlayer while the default is MediaPlayer

I know Process and ProcessStartInfo method, but I would like to know how to "open program with..."

Can you help me, plz?

Answer 1

Okay, so thought I'd make this possible for you before I clock off for the night. I have thrown together a working console application which loads (known) installed programs from the registry's App Path key. The solution is far from perfect, won't be the safest, fastest, or most reliable solution, and it certainly shouldn't be seen amongst any production code, but it is more than enough to aid you, hopefully, in developing what it is you need:

So, here is the code, minus the namespace...

using System;
using System.IO;
using Microsoft.Win32;
using System.Diagnostics;
using System.Collections.Generic;

class Program
{
    static void Main(string[] args)
    {
        if (args.Length >= 0 && !string.IsNullOrEmpty(args[0]) && File.Exists(args[0]))
        {
            var programs = new InstalledPrograms();
            var programKey = "RealPlay.exe".ToLowerInvariant();
            if (programs.ContainsKey(programKey))
            {
                var programPath = programs[programKey];
                if (!string.IsNullOrEmpty(programPath) && File.Exists(programPath))
                {
                    var process = new Process();
                    process.StartInfo = new ProcessStartInfo(programPath);
                    process.StartInfo.Arguments = args[0];
                    if (process.Start())
                    {
                        Console.WriteLine("That was easy!");
                    }
                    else
                    {
                        Console.WriteLine("Hell's bells and buckets of blood, we seem to have hit a snag!");
                    }
                }
            }
        }
        else
        {
            Console.WriteLine("Specify a file as an argument, silly!");
        }
        Console.WriteLine();
        Console.WriteLine("Press any key to exit...");
        Console.ReadKey();
    }

    class InstalledPrograms : Dictionary<string, string>
    {
        static string PathKeyName = "Path";
        static string RegistryKeyToAppPaths = @"SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths";           

        public InstalledPrograms()
        {
            Refresh();
        }

        public void Refresh()
        {
            Clear();
            using (var registryKey = Registry.LocalMachine.OpenSubKey(RegistryKeyToAppPaths))
            {
                var executableFullPath = string.Empty;
                foreach (var registrySubKeyName in registryKey.GetSubKeyNames())
                {
                    using (var registrySubKey = registryKey.OpenSubKey(registrySubKeyName))
                    {
                        executableFullPath = registrySubKey.GetValue(string.Empty) as string;
                        Add(registrySubKeyName.ToLowerInvariant(), executableFullPath);
                    }
                }
            }
        }
    }
}

Though we check for file existence, and other minor but necessary checks are made, you would still need to tighten this up further when plugged into the environment of your own code, including, among other things, exception handling for, but not limited to, registry access issues.