/// <summary>
/// Gets the file association information.
/// </summary>
/// <param name="fileExtension">The file extension part.</param>
/// <returns>The file association information; or null, if not found or failure.</returns>
public static FileAssociationInfo GetFileAssociationInfo(string fileExtension)
{
fileExtension = fileExtension?.Trim()?.ToLowerInvariant();
if (string.IsNullOrEmpty(fileExtension))
{
return(null);
}
var info = new FileAssociationInfo
{
FileExtension = fileExtension
};
using var ext = RegistryUtility.TryOpenSubKey(Reg.ClassesRoot, fileExtension);
string h;
if (ext == null)
{
if (fileExtension.IndexOf('/') < 1)
{
return(info);
}
using var mime = RegistryUtility.TryOpenSubKey(Reg.ClassesRoot, "MIME\\Database\\Content Type\\" + fileExtension);
if (mime == null)
{
return(info);
}
info.ContentType = fileExtension;
fileExtension = RegistryUtility.TryGetStringValue(mime, "Extension");
info.FileExtension = fileExtension;
using var ext2 = RegistryUtility.TryOpenSubKey(Reg.ClassesRoot, fileExtension);
if (ext2 == null)
{
return(info);
}
h = RegistryUtility.TryGetStringValue(ext2, null);
}
else
{
info.ContentType = RegistryUtility.TryGetStringValue(ext, "Content Type");
h = RegistryUtility.TryGetStringValue(ext, null);
}
if (string.IsNullOrEmpty(h))
{
using var ext2 = RegistryUtility.TryOpenSubKey(ext, "OpenWithProgids");
if (ext2 == null)
{
return(info);
}
h = RegistryUtility.TryGetValueNames(ext2).FirstOrDefault(ele => !string.IsNullOrWhiteSpace(ele));
if (string.IsNullOrEmpty(h))
{
return(info);
}
}
using var assoc = RegistryUtility.TryOpenSubKey(Reg.ClassesRoot, h);
if (assoc == null)
{
return(info);
}
info.Name = RegistryUtility.TryGetStringValue(assoc, null) ?? RegistryUtility.TryGetStringValue(assoc, "FriendlyTypeName");
using var icon = RegistryUtility.TryOpenSubKey(assoc, "DefaultIcon");
if (icon != null)
{
info.Icon = RegistryUtility.TryGetStringValue(icon, null);
}
using var shell = RegistryUtility.TryOpenSubKey(assoc, "shell");
if (shell == null)
{
return(info);
}
var defaultCommand = RegistryUtility.TryGetStringValue(shell, null);
var commands = RegistryUtility.TryOpenSubKeys(shell)?.ToList();
if (commands.Count < 1)
{
return(info);
}
foreach (var command in commands)
{
var name = command.Name;
var pos = name?.LastIndexOf('\\') ?? -1;
if (pos >= 0)
{
name = name.Substring(pos + 1);
}
var cmd = new FileOpenCommandInfo
{
Key = name,
Name = RegistryUtility.TryGetStringValue(command, null)
};
var exe = RegistryUtility.TryOpenSubKey(command, "command");
if (exe == null)
{
continue;
}
var c = RegistryUtility.TryGetStringValue(exe, null);
if (string.IsNullOrWhiteSpace(c))
{
continue;
}
cmd.Command = c;
info.Commands.Add(cmd);
}
if (!string.IsNullOrWhiteSpace(defaultCommand))
{
info.DefaultCommand = info.Commands.FirstOrDefault(ele => defaultCommand.Equals(ele.Key, StringComparison.OrdinalIgnoreCase));
}
if (info.DefaultCommand == null)
{
info.DefaultCommand = info.Commands.FirstOrDefault();
}
return(info);
}