using System.Runtime.InteropServices;
using System;


public class ChinarFileDlog
{
    public int structSize = 0;
    public IntPtr dlgOwner = IntPtr.Zero;
    public IntPtr instance = IntPtr.Zero;
    public string filter = null;
    public string customFilter = null;
    public int maxCustFilter = 0;
    public int filterIndex = 0;
    public string file = null;
    public int maxFile = 0;
    public string fileTitle = null;
    public int maxFileTitle = 0;
    public string initialDir = null;
    public string title = null;
    public int flags = 0;
    public short fileOffset = 0;
    public short fileExtension = 0;
    public string defExt = null;
    public IntPtr custData = IntPtr.Zero;
    public IntPtr hook = IntPtr.Zero;
    public string templateName = null;
    public IntPtr reservedPtr = IntPtr.Zero;
    public int reservedInt = 0;
    public int flagsEx = 0;
}

public class OpenFileDialog
{
    [DllImport("Comdlg32.dll", SetLastError = true, ThrowOnUnmappableChar = true, CharSet = CharSet.Auto)]
    public static extern bool GetOpenFileName([In, Out] ChinarFileDlog ofd);
}

public class FolderSelectDialog
{
    private const uint BIF_RETURNONLYFSDIRS = 0x0001;

    [DllImport("shell32.dll")]
    private static extern IntPtr SHBrowseForFolder(ref BROWSEINFO lpbi);

    [DllImport("shell32.dll", CharSet = CharSet.Unicode)]
    private static extern bool SHGetPathFromIDList(IntPtr pidl, IntPtr pszPath);

    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
    private struct BROWSEINFO
    {
        public IntPtr hwndOwner;
        public IntPtr pidlRoot;
        public IntPtr pszDisplayName;
        public string lpszTitle;
        public uint ulFlags;
        public IntPtr lpfn;
        public IntPtr lParam;
        public int iImage;
    }

    public static string OpenFolderDialog(string title)
    {
        string selectedPath = string.Empty;

        var bi = new BROWSEINFO();
        bi.hwndOwner = IntPtr.Zero;
        bi.ulFlags = BIF_RETURNONLYFSDIRS;
        bi.lpszTitle = title;

        IntPtr pidl = SHBrowseForFolder(ref bi);
        if (pidl != IntPtr.Zero)
        {
            var path = Marshal.AllocHGlobal(260 * sizeof(char));
            if (SHGetPathFromIDList(pidl, path))
            {
                selectedPath = Marshal.PtrToStringUni(path);
            }
            Marshal.FreeHGlobal(path);
            Marshal.FreeCoTaskMem(pidl);
        }

        return selectedPath;
    }
}