Is it possible to select a custom start path in modified FolderBrowser Dialog

Question

Frustrated with the FolderBrowserDialog class UI, I decided to use this implementation which provides more user friendly features such as showing the folder path.

https://support.microsoft.com/en-ca/kb/306285

Unfortunately, the startLocation property only includes a few enumerated locations such as Desktop, MyDocuments, ect.

Is there a way I can modify this example to accept any file path?

Thanks!

score 2 · Answer 1 · answered Jun 27 '16 at 19:28

Try this

public delegate int BrowseCallbackProc(IntPtr hwnd, int uMsg, IntPtr wParam, IntPtr lParam);

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
[ComVisible(true)]
public class BROWSEINFO
{
    public IntPtr hwndOwner;
    public IntPtr pidlRoot;
    public IntPtr pszDisplayName;
    public string lpszTitle;
    public int ulFlags;
    public BrowseCallbackProc lpfn;
    public IntPtr lParam;
    public int iImage;

}

public class Win32SDK
{
    [DllImport("shell32.dll", PreserveSig = true, CharSet = CharSet.Auto)]
    public static extern IntPtr SHBrowseForFolder(BROWSEINFO bi);

    [DllImport("shell32.dll", PreserveSig = true, CharSet = CharSet.Auto)]
    public static extern bool SHGetPathFromIDList(IntPtr pidl, IntPtr pszPath);

    [DllImport("shell32.dll", PreserveSig = true, CharSet = CharSet.Auto)]
    public static extern int SHGetSpecialFolderLocation(IntPtr hwnd, int csidl, ref IntPtr ppidl);

    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = false)]
    public static extern IntPtr SendMessage(IntPtr hWnd, int Msg, int wParam, string lParam);

}

public enum BrowseForFolderMessages
{
    BFFM_ENABLEOK = 0x465,
    BFFM_INITIALIZED = 1,
    BFFM_IUNKNOWN = 5,
    BFFM_SELCHANGED = 2,
    BFFM_SETEXPANDED = 0x46a,
    BFFM_SETOKTEXT = 0x469,
    BFFM_SETSELECTIONA = 0x466,
    BFFM_SETSELECTIONW = 0x467,
    BFFM_SETSTATUSTEXTA = 0x464,
    BFFM_SETSTATUSTEXTW = 0x468,
    BFFM_VALIDATEFAILEDA = 3,
    BFFM_VALIDATEFAILEDW = 4
}

[Flags, Serializable]
public enum BrowseFlags
{
    BIF_DEFAULT = 0x0000,
    BIF_BROWSEFORCOMPUTER = 0x1000,
    BIF_BROWSEFORPRINTER = 0x2000,
    BIF_BROWSEINCLUDEFILES = 0x4000,
    BIF_BROWSEINCLUDEURLS = 0x0080,
    BIF_DONTGOBELOWDOMAIN = 0x0002,
    BIF_EDITBOX = 0x0010,
    BIF_NEWDIALOGSTYLE = 0x0040,
    BIF_NONEWFOLDERBUTTON = 0x0200,
    BIF_RETURNFSANCESTORS = 0x0008,
    BIF_RETURNONLYFSDIRS = 0x0001,
    BIF_SHAREABLE = 0x8000,
    BIF_STATUSTEXT = 0x0004,
    BIF_UAHINT = 0x0100,
    BIF_VALIDATE = 0x0020,
    BIF_NOTRANSLATETARGETS = 0x0400,
}

public class FolderBrowser
{
    private string m_strTitle;
    private BrowseFlags m_Flags;
    private string m_initDir;

    public FolderBrowser()
    {
        m_Flags = BrowseFlags.BIF_DEFAULT;
        m_strTitle = "";
    }

    public string DirectoryPath { get; private set; }

    public string DisplayName { get; private set; }

    public string Title
    {
        set { m_strTitle = value; }
    }

    public BrowseFlags Flags
    {
        set { m_Flags = value; }
    }

    public DialogResult ShowDialog()
    {
        BROWSEINFO bi = new BROWSEINFO();

        bi.pszDisplayName = IntPtr.Zero;
        bi.lpfn = IntPtr.Zero;
        bi.lpfn = BrowserCallBack;
        bi.lParam = IntPtr.Zero;
        bi.lpszTitle = "Select Folder";

        IntPtr idListPtr = IntPtr.Zero;
        IntPtr pszPath = IntPtr.Zero;

        try
        {
            if (m_strTitle.Length != 0)
            {
                bi.lpszTitle = m_strTitle;
            }
            bi.ulFlags = (int)m_Flags;
            bi.pszDisplayName = Marshal.AllocHGlobal(256);
            // Call SHBrowseForFolder
            idListPtr = Win32SDK.SHBrowseForFolder(bi);

            // Check if the user cancelled out of the dialog or not.
            if (idListPtr == IntPtr.Zero)
            {
                return DialogResult.Cancel;
            }

            // Allocate ncessary memory buffer to receive the folder path.
            pszPath = Marshal.AllocHGlobal(256);
            // Call SHGetPathFromIDList to get folder path.
            bool bRet = Win32SDK.SHGetPathFromIDList(idListPtr, pszPath);
            // Convert the returned native poiner to string.
            DirectoryPath = Marshal.PtrToStringAuto(pszPath);
            DisplayName = Marshal.PtrToStringAuto(bi.pszDisplayName);
        }
        catch (Exception ex)
        {
            Trace.WriteLine(ex.Message);
            return DialogResult.Abort;
        }
        finally
        {
            // Free the memory allocated by shell.
            if (idListPtr != IntPtr.Zero)
            {
                Marshal.FreeHGlobal(idListPtr);
            }
            if (pszPath != IntPtr.Zero)
            {
                Marshal.FreeHGlobal(pszPath);
            }
            Marshal.FreeHGlobal(bi.pszDisplayName);
        }
        return DialogResult.OK;
    }

    private IntPtr GetStartLocationPath()
    {
        return IntPtr.Zero;
    }

    public string InitDir
    {
        set { m_initDir = value; }
    }

    private int BrowserCallBack(IntPtr hWnd, int uMsg, IntPtr wParam, IntPtr lParam)
    {
        if (uMsg == (int)BrowseForFolderMessages.BFFM_INITIALIZED)
        {
            Win32SDK.SendMessage(hWnd, (int)BrowseForFolderMessages.BFFM_SETSELECTIONW, 1, m_initDir);
        }

        return 0;
    }
}

Usage:

FolderBrowser browser = new FolderBrowser();
browser.Title = "Browse folder";
browser.Flags = BrowseFlags.BIF_NEWDIALOGSTYLE |    BrowseFlags.BIF_NONEWFOLDERBUTTON;
browser.InitDir = Application.StartupPath; // <-- Start path

if (browser.ShowDialog() == DialogResult.OK)
{
    string selectedDirectory = browser.DirectoryPath;
}

Is it possible to select a custom start path in modified FolderBrowser Dialog

1 Answers1