Why FolderBrowserDialog dialog does not scroll to selected folder?

Question

As show in this screen shot, the selected folder is not in the view. It needs to be scrolled down to view the selected folder.

Answer 1

I run into same problem in c++ /mfc. It worked for me to use ::PostMessage rather than ::SendMessage in the BFFM_INITIALIZED callback to place the TVM_ENSUREVISIBLE msg

    case BFFM_INITIALIZED: 
{
// select something
::SendMessage(m_hDialogBox, BFFM_SETSELECTION, TRUE, (LPARAM) pszSelection);


// find tree control
m_hTreeCtrl = 0;
HWND hchild = GetWindow(hWnd, GW_CHILD) ;
while (hchild != NULL)
{
  VS_TChar classname[200] ;
  GetClassName(hchild, classname, 200) ;

  if (VS_strcmp(classname, _T("SHBrowseForFolder ShellNameSpace Control")) == 0)
  {
    HWND hlistctrl = GetWindow(hchild, GW_CHILD) ;
    do
    { 
      GetClassName(hlistctrl, classname, 200) ;
      if (lstrcmp(classname, _T("SysTreeView32")) == 0)
      {
        m_hTreeCtrl = hlistctrl;
        break ;   
      }

      hlistctrl = GetWindow(hlistctrl, GW_HWNDNEXT) ;
    } while (hlistctrl != NULL);
  }      
  if (m_hTreeCtrl)
    break;
  hchild = GetWindow(hchild, GW_HWNDNEXT);      
}

if (m_hTreeCtrl)
{
  int item = ::SendMessage(m_hTreeCtrl, TVM_GETNEXTITEM, TVGN_CARET, 0);
  if (item != 0)             
    ::PostMessage(m_hTreeCtrl, TVM_ENSUREVISIBLE,0,item);
}
break;
}

Answer 2

In response to Marc F's post - I've converted the VB.Net to C#

    public enum GW
    {
        HWNDFIRST = 0,
        HWNDLAST = 1,
        HWNDNEXT = 2,
        HWNDPREV = 3,
        OWNER = 4,
        CHILD = 5,
        ENABLEDPOPUP = 6
    }

    [System.Runtime.InteropServices.DllImport("user32.dll", EntryPoint = "SendMessageW", ExactSpelling = true, CharSet = System.Runtime.InteropServices.CharSet.Ansi, SetLastError = true)]
    public static extern IntPtr SendMessageW(IntPtr hWnd, uint msg, int wParam, [MarshalAs(UnmanagedType.LPWStr)] string lParam);
    [System.Runtime.InteropServices.DllImport("user32.dll", EntryPoint = "FindWindowExW", ExactSpelling = true, CharSet = System.Runtime.InteropServices.CharSet.Ansi, SetLastError = true)]
    public static extern IntPtr FindWindowExW(IntPtr hWndParent, IntPtr hWndChildAfter, [MarshalAs(UnmanagedType.LPWStr)] string lpszClass, [MarshalAs(UnmanagedType.LPWStr)] string lpszWindow);
    [System.Runtime.InteropServices.DllImport("user32", EntryPoint = "GetWindow", ExactSpelling = true, CharSet = System.Runtime.InteropServices.CharSet.Ansi, SetLastError = true)]
    public static extern UInt32 GetWindow(IntPtr hwnd, UInt32 wCmd);
    [System.Runtime.InteropServices.DllImport("user32", EntryPoint = "GetDesktopWindow", ExactSpelling = true, CharSet = System.Runtime.InteropServices.CharSet.Ansi, SetLastError = true)]
    public static extern IntPtr GetDesktopWindow();
    [System.Runtime.InteropServices.DllImport("user32", EntryPoint = "GetClassNameA", ExactSpelling = true, CharSet = System.Runtime.InteropServices.CharSet.Ansi, SetLastError = true)]
    public static extern int GetClassName(IntPtr hwnd, System.Text.StringBuilder lpClassName, int nMaxCount);

    private void FolderBrowserDialog_EnsureVisible(FolderBrowserDialog FB, IntPtr _Owner)
    {
        IntPtr hwnd = System.IntPtr.Zero;
        System.Text.StringBuilder sClassname = new System.Text.StringBuilder(256);
        Thread.Sleep(50); //necessary to let FolderBrowserDialog construct its window
        hwnd = GetDesktopWindow(); //Desktop window handle.
        hwnd = (System.IntPtr)GetWindow(hwnd, (UInt32)GW.CHILD); //We will find all children.
        while (!(hwnd == (System.IntPtr)0))
        {
            if (GetWindow(hwnd, (UInt32)GW.OWNER) == (UInt32)_Owner) //If one window is owned by our main window...
            {
                GetClassName(hwnd, sClassname, 255);
                if (sClassname.ToString() == "#32770") //Check if the class is FolderBrowserDialog.
                {
                    break; //Then we found it.
                }
            }
            hwnd = (System.IntPtr)GetWindow(hwnd, (UInt32)GW.HWNDNEXT); //Next window.
        } //If no found then exit.
        if (hwnd == (System.IntPtr)0)
        {
            return;
        }
        IntPtr hChild = (System.IntPtr)0;
        IntPtr hTreeView = (System.IntPtr)0;
        int i = 0;
        do
        {
            i += 1;
            if (i > 1000) //Security to avoid infinite loop.
            {
                return;
            }
            hChild = FindWindowExW(hwnd, hChild, null, null); //Look for children windows of FolderBrowserDialog.
            hTreeView = FindWindowExW(hChild, (System.IntPtr)0, "SysTreeView32", null); //Look for treeview of FolderBrowserDialog.
            Thread.Sleep(5); //delay necessary because FolderBrowserDialog is in construction, then treeview maybe not yet exist.
        } while (hTreeView == (System.IntPtr)0);
        if (SendMessageW(hwnd, 0x46A, 1, FB.SelectedPath) == (System.IntPtr)0) //Send message BFFM_SETEXPANDED to FolderBrowserDialog.
        {
            SendMessageW(hTreeView, 0x7, 0, null); //Send message WM_SETFOCUS to the treeeview.
        }
    }

Tested this and it works fine. Make sure you reference System.Runtime.InteropServices, System.Threading, an System.Threading.Tasks