/// <summary>
/// Shows the dialog box to let the user browse for and select a folder.
/// </summary>
/// <param name="parentWindowHandle">The HWND of the parent window.</param>
/// <returns>The selected folder or <c>null</c> if no folder was selected by the user.</returns>
protected override bool RunDialog(IntPtr parentWindowHandle)
{
// Make sure OLE is initialized. This is a prerequisite for calling SHBrowseForFolder.
NativeMethods.OleInitialize(IntPtr.Zero);
IntPtr rpidl = IntPtr.Zero;
NativeMethods.SHGetSpecialFolderLocation(parentWindowHandle, (int)RootFolder, out rpidl);
if (rpidl == IntPtr.Zero)
{
NativeMethods.SHGetSpecialFolderLocation(parentWindowHandle, 0, out rpidl);
if (rpidl == IntPtr.Zero)
{
throw new InvalidOperationException("No root folder specified for FolderBrowserDialog2.");
}
}
if (Control.CheckForIllegalCrossThreadCalls && (Application.OleRequired() != System.Threading.ApartmentState.STA))
{
throw new System.Threading.ThreadStateException("Debugging Exception Only. Thread must be STA.");
}
BrowseInfoFlag browseInfoFlag = BrowseInfoFlag.BIF_NEWDIALOGSTYLE | BrowseInfoFlag.BIF_SHAREABLE;
if (!ShowNewFolderButton)
{
browseInfoFlag |= BrowseInfoFlag.BIF_NONEWFOLDERBUTTON;
}
if (ShowFolderPathEditBox)
{
browseInfoFlag |= BrowseInfoFlag.BIF_EDITBOX | BrowseInfoFlag.BIF_VALIDATE;
}
if (ShowFiles)
{
browseInfoFlag |= BrowseInfoFlag.BIF_BROWSEINCLUDEFILES;
}
browseInfoFlag |= (BrowseInfoFlag)BrowserFlag;
NativeMethods.BROWSEINFO bi;
bi.hwndOwner = parentWindowHandle;
bi.pidlRoot = rpidl;
bi.pszDisplayName = new string('\0', 260);
bi.lpszTitle = Description;
bi.ulFlags = (uint)browseInfoFlag;
bi.lpfn = new NativeMethods.BrowseCallBackProc(OnBrowseEvent);
bi.lParam = IntPtr.Zero;
bi.iImage = 0;
StringBuilder sb = new StringBuilder(260);
IntPtr pidl = IntPtr.Zero;
try
{
pidl = NativeMethods.SHBrowseForFolder(ref bi);
if (((browseInfoFlag & BrowseInfoFlag.BIF_BROWSEFORPRINTER) == BrowseInfoFlag.BIF_BROWSEFORPRINTER) ||
((browseInfoFlag & BrowseInfoFlag.BIF_BROWSEFORCOMPUTER) == BrowseInfoFlag.BIF_BROWSEFORCOMPUTER))
{
SelectedPath = bi.pszDisplayName;
}
else
{
if (pidl == IntPtr.Zero || 0 == NativeMethods.SHGetPathFromIDList(pidl, sb))
{
return(false);
}
SelectedPath = sb.ToString();
}
return(true);
}
finally
{
if (rpidl != IntPtr.Zero)
{
Marshal.FreeCoTaskMem(rpidl);
}
if (pidl != IntPtr.Zero)
{
Marshal.FreeCoTaskMem(pidl);
}
}
}