How to get recommended programs associated with file extension in C#

user_247189 0
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I want to get path to the programs that associated with file extension, preferably through Win32 API.

  1. List of programs that appears in "Open With" menu item
  2. List of programs that appears as recommended in "Open With..." dialog.

UPD:

Assume that i have office11 and office12 installed on my machine, default program for .xls is office 11. If look at HKEY_CLASSES_ROOT\Excel.Sheet.8\shell\Open\command there is a path to office11 excel.exe, but when i right click on file i can choose office12 in Open With menu item. So where is this association stored?

I'm using C#.

Thanks.

file-association windows c#
3 Answers

I improved method by LarsTech. Now it returns paths to programs.

public List<string> RecommendedPrograms(string ext)
{
  //Search programs names:
  List<string> names = new List<string>();
  string baseKey = @"Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\." + ext;
  string s;

  using (RegistryKey rk = Registry.CurrentUser.OpenSubKey(baseKey + @"\OpenWithList"))
  {
    if (rk != null)
    {
      string mruList = (string)rk.GetValue("MRUList");
      if (mruList != null)
      {
        foreach (char c in mruList)
        {
          s = rk.GetValue(c.ToString()).ToString();
          if (s.ToLower().Contains(".exe"))
            names.Add(s);
        }
      }
    }
  }

  if (names.Count == 0)
    return names;

  //Search paths:
  List<string> paths = new List<string>();
  baseKey = @"Software\Classes\Applications\{0}\shell\open\command";

  foreach (string name in names)
    using (RegistryKey rk = Registry.CurrentUser.OpenSubKey(String.Format(baseKey, name)))
    {
      if (rk != null)
      {
        s = rk.GetValue("").ToString();
        s = s.Substring(1, s.IndexOf("\"", 2) - 1); //remove quotes
        paths.Add(s);
      }
    }

  if (paths.Count > 0)
    return paths;

  //Search pathes for Windows XP:
  foreach (string name in names)
    using (RegistryKey rk = Registry.LocalMachine.OpenSubKey(String.Format(baseKey, name)))
    {
      if (rk != null)
      {
        s = rk.GetValue("").ToString();
        s = s.Substring(1, s.IndexOf("\"", 2) - 1); //remove quotes
        paths.Add(s);
      }
    }

  return paths;
}
user_29568300
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