Returns path to the application folder in %LOCALAPPDATA%

ApplicationFolderPath.cs

private static string _localAppFolderPath = null;
/// <summary>
/// Путь к папке программы в локальной папке пользователя.
/// </summary>
public static string ApplicationFolderPath
{
    get
    {
        if (_localAppFolderPath != null)
        {
            return _localAppFolderPath;
        }

        string localAppDataPath = Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData, Environment.SpecialFolderOption.Create);

        StringBuilder sb = new StringBuilder(localAppDataPath);
        sb.Append(Path.DirectorySeparatorChar);
        Assembly assembly = Assembly.GetExecutingAssembly();
        sb.Append(assembly.GetCustomAttribute<AssemblyCompanyAttribute>().Company);
        sb.Append(Path.DirectorySeparatorChar);
        sb.Append(assembly.GetCustomAttribute<AssemblyProductAttribute>().Product);
        sb.Append(Path.DirectorySeparatorChar);
        _localAppFolderPath = sb.ToString();
        Directory.CreateDirectory(_localAppFolderPath);

        return _localAppFolderPath;
    }
}