private int OnBrowseEvent(IntPtr hWnd, int msg, IntPtr lp, IntPtr lpData)
{
switch (msg)
{
case WindowsInterop.BFFM_INITIALIZED: // Required to set initialPath
{
//Win32.SendMessage(new HandleRef(null, hWnd), BFFM_SETSELECTIONA, 1, lpData);
// Use BFFM_SETSELECTIONW if passing a Unicode string, i.e. native CLR Strings.
if (!string.IsNullOrEmpty(_initialPath))
{
WindowsInterop.SendMessage(new HandleRef(null, hWnd), WindowsInterop.BFFM_SETSELECTIONW, 1, _initialPath);
}
break;
}
case WindowsInterop.BFFM_SELCHANGED:
{
var pathPtr = Marshal.AllocHGlobal(260 * Marshal.SystemDefaultCharSize);
if (WindowsInterop.SHGetPathFromIDList(lp, pathPtr))
{
WindowsInterop.SendMessage(new HandleRef(null, hWnd), WindowsInterop.BFFM_SETSTATUSTEXTW, 0, pathPtr);
}
Marshal.FreeHGlobal(pathPtr);
break;
}
}
return(0);
}
private DialogResponse SelectFolderInternal(string message, FileDialogOptions options)
{
if (Directory.Exists(options.Directory))
{
_initialPath = options.Directory;
}
var pIdList = IntPtr.Zero;
var sb = new StringBuilder(256);
var bufferAddress = Marshal.AllocHGlobal(256);
var bi = new WindowsInterop.BROWSEINFO
{
hwndOwner = IntPtr.Zero,
pidlRoot = IntPtr.Zero,
pszDisplayName = message,
lpszTitle = options.Title,
ulFlags = WindowsInterop.BIF_NEWDIALOGSTYLE | WindowsInterop.BIF_SHAREABLE,
lpfn = OnBrowseEvent,
lParam = IntPtr.Zero,
iImage = 0
};
try
{
pIdList = WindowsInterop.SHBrowseForFolder(ref bi);
if (pIdList == IntPtr.Zero)
{
return(new DialogResponse {
IsCanceled = true
});
}
if (true != WindowsInterop.SHGetPathFromIDList(pIdList, bufferAddress))
{
return(new DialogResponse {
Value = string.Empty
});
}
sb.Append(Marshal.PtrToStringAuto(bufferAddress));
}
finally
{
// Caller is responsible for freeing this memory.
Marshal.FreeCoTaskMem(pIdList);
}
return(new DialogResponse {
Value = sb.ToString()
});
}