Try calling the ChangeDirectory() function before using the FolderBrowser.

Maybe it'll fix the problem (if the FolderBrowser itself doesn't change any 'internal' directories by accessing files.

regards.

No, none of that matters to this call inside that visual studio dll it will not care what your apps current directory is only what the last used folder the common item dialog used.

SetCurrentDirectory or ChangeDirectory all did not work.

However, good news is it was much simpler than i imagined, I just opened the FolderBrowser2 sample source in Visual Studios 2019 and modified the FolderBrowser2.cs source script to add a few lines and updated the ShowDialog() to add another string argument, tested the directory provided if it was valid and now if we pass in a valid UNC or Directory path on the machine the PB app is run on the dialog is now opening to the directory desired.

Its really the best solution so far so I am just going to run with it.

Thanks for the suggestions guys I was just trying to avoid modifying the original sample dll but life is never as easy as that anyhow its done.



sample of the updated FolderBrowser2.cs that works to add the parm for setting the default folder:



using System;

using System.Runtime.InteropServices;

using System.IO;



namespace FolderBrowser2

{

public class FolderBrowser2

{

public string DirectoryPath { get; set; }



public int ShowDialog( ulong handle, string strStartPath){



IntPtr hwndOwner = (IntPtr)handle;



IFileOpenDialog dialog = (IFileOpenDialog)new FileOpenDialog();

try

{

IShellItem item;



if (!string.IsNullOrEmpty(strStartPath))

{

if (Directory.Exists(strStartPath))

{

DirectoryPath = strStartPath;

}

}





if (!string.IsNullOrEmpty(DirectoryPath))

{

IntPtr idl;

uint atts = 0;

if (SHILCreateFromPath(DirectoryPath, out idl, ref atts) == 0)

{

if (SHCreateShellItem(IntPtr.Zero, IntPtr.Zero, idl, out item) == 0)

{

dialog.SetFolder(item);

}

}

}

dialog.SetOptions(FOS.FOS_PICKFOLDERS | FOS.FOS_FORCEFILESYSTEM);

uint hr = dialog.Show(hwndOwner);

if (hr == ERROR_CANCELLED)

return FB2_CANCEL;



if (hr != 0)

return FB2_ERROR;



dialog.GetResult(out item);

string path;

item.GetDisplayName(SIGDN.SIGDN_FILESYSPATH, out path);

DirectoryPath = path;

return FB2_SUCCESS;

}

finally

{

Marshal.ReleaseComObject(dialog);

}

}



[DllImport("shell32.dll")]

private static extern int SHILCreateFromPath([MarshalAs(UnmanagedType.LPWStr)] string pszPath, out IntPtr ppIdl, ref uint rgflnOut);



[DllImport("shell32.dll")]

private static extern int SHCreateShellItem(IntPtr pidlParent, IntPtr psfParent, IntPtr pidl, out IShellItem ppsi);



[DllImport("user32.dll")]

private static extern IntPtr GetActiveWindow();



private const uint ERROR_CANCELLED = 0x800704C7;

private const int FB2_SUCCESS = 1;

private const int FB2_CANCEL = 0;

private const int FB2_ERROR = -1;



[ComImport]

[Guid("DC1C5A9C-E88A-4dde-A5A1-60F82A20AEF7")]

private class FileOpenDialog

{

}



[ComImport]

[Guid("42f85136-db7e-439c-85f1-e4075d135fc8")]

[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]

private interface IFileOpenDialog

{

[PreserveSig]

uint Show([In] IntPtr parent); // IModalWindow

void SetFileTypes(); // not fully defined

void SetFileTypeIndex([In] uint iFileType);

void GetFileTypeIndex(out uint piFileType);

void Advise(); // not fully defined

void Unadvise();

void SetOptions([In] FOS fos);

void GetOptions(out FOS pfos);

void SetDefaultFolder(IShellItem psi);

void SetFolder(IShellItem psi);

void GetFolder(out IShellItem ppsi);

void GetCurrentSelection(out IShellItem ppsi);

void SetFileName([In, MarshalAs(UnmanagedType.LPWStr)] string pszName);

void GetFileName([MarshalAs(UnmanagedType.LPWStr)] out string pszName);

void SetTitle([In, MarshalAs(UnmanagedType.LPWStr)] string pszTitle);

void SetOkButtonLabel([In, MarshalAs(UnmanagedType.LPWStr)] string pszText);

void SetFileNameLabel([In, MarshalAs(UnmanagedType.LPWStr)] string pszLabel);

void GetResult(out IShellItem ppsi);

void AddPlace(IShellItem psi, int alignment);

void SetDefaultExtension([In, MarshalAs(UnmanagedType.LPWStr)] string pszDefaultExtension);

void Close(int hr);

void SetClientGuid(); // not fully defined

void ClearClientData();

void SetFilter([MarshalAs(UnmanagedType.Interface)] IntPtr pFilter);

void GetResults([MarshalAs(UnmanagedType.Interface)] out IntPtr ppenum); // not fully defined

void GetSelectedItems([MarshalAs(UnmanagedType.Interface)] out IntPtr ppsai); // not fully defined

}



[ComImport]

[Guid("43826D1E-E718-42EE-BC55-A1E261C37BFE")]

[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]

private interface IShellItem

{

void BindToHandler(); // not fully defined

void GetParent(); // not fully defined

void GetDisplayName([In] SIGDN sigdnName, [MarshalAs(UnmanagedType.LPWStr)] out string ppszName);

void GetAttributes(); // not fully defined

void Compare(); // not fully defined

}



private enum SIGDN : uint

{

SIGDN_DESKTOPABSOLUTEEDITING = 0x8004c000,

SIGDN_DESKTOPABSOLUTEPARSING = 0x80028000,

SIGDN_FILESYSPATH = 0x80058000,

SIGDN_NORMALDISPLAY = 0,

SIGDN_PARENTRELATIVE = 0x80080001,

SIGDN_PARENTRELATIVEEDITING = 0x80031001,

SIGDN_PARENTRELATIVEFORADDRESSBAR = 0x8007c001,

SIGDN_PARENTRELATIVEPARSING = 0x80018001,

SIGDN_URL = 0x80068000

}



[Flags]

private enum FOS

{

FOS_ALLNONSTORAGEITEMS = 0x80,

FOS_ALLOWMULTISELECT = 0x200,

FOS_CREATEPROMPT = 0x2000,

FOS_DEFAULTNOMINIMODE = 0x20000000,

FOS_DONTADDTORECENT = 0x2000000,

FOS_FILEMUSTEXIST = 0x1000,

FOS_FORCEFILESYSTEM = 0x40,

FOS_FORCESHOWHIDDEN = 0x10000000,

FOS_HIDEMRUPLACES = 0x20000,

FOS_HIDEPINNEDPLACES = 0x40000,

FOS_NOCHANGEDIR = 8,

FOS_NODEREFERENCELINKS = 0x100000,

FOS_NOREADONLYRETURN = 0x8000,

FOS_NOTESTFILECREATE = 0x10000,

FOS_NOVALIDATE = 0x100,

FOS_OVERWRITEPROMPT = 2,

FOS_PATHMUSTEXIST = 0x800,

FOS_PICKFOLDERS = 0x20,

FOS_SHAREAWARE = 0x4000,

FOS_STRICTFILETYPES = 4

}

}

}

Glad you solved it and thanks for sharing!