Windows Mobile Programming Tricks on the .NET Compact Framework: Part 1

using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;

namespace BeeMobile
{
    public class NativeFileSystem
    {
        const int MAX_PATH = 50;
        static bool m_sbExceptionsEnabled;

        [DllImport("coredll.dll", SetLastError = true, EntryPoint = "SHGetSpecialFolderPath")]
        static extern bool SHGetSpecialFolderPath(int hwndOwner, string lpszPath, Folders nFolder, bool fCreate);

        NativeFileSystem()
        { }

        public static string GetFolderPath(Folders folder)
        {
            string sPath = new string(' ', MAX_PATH);
            bool bRet;

            try
            {
                bRet = SHGetSpecialFolderPath(0, sPath, folder, false);
            }
            catch (Exception ex)
            {
                HandleCeError(ex, "GetFolderPath");
                return null;
            }

            if (!bRet)
            {
                int errorNum = Marshal.GetLastWin32Error();
                HandleCeError(new WinCeException("SHGetSpecialFolderPath returned false, likely an invalid constant", errorNum), "GetSpecialFolderPath");
            }

            return sPath;
        }

        private static void HandleCeError(Exception ex, string method)
        {
            // logging

            if (!ExceptionsEnabled)
            {
                return;
            }

            if (ex is NotSupportedException)
            {
                throw new WinCeException("Bad arguments or incorrect declaration in " + method, 0, ex);
            }

            if (ex is MissingMethodException)
            {
                throw new WinCeException("Entry point not found in " + method, 0, ex);
            }

            if (ex is WinCeException)
            {
                throw ex;
            }

            throw new WinCeException("Miscellaneous exception in " + method, 0, ex);
        }


        #region Properties
        public static bool ExceptionsEnabled
        {
            get
            {
                return m_sbExceptionsEnabled;
            }
            set
            {
                m_sbExceptionsEnabled = value;
            }
        }
        #endregion
    }
}