在Microsoft.Win32.OpenFileDialog上调用ShowDialog时出现异常

Question

I'm getting reports from a WPF application that is deployed in the field that the following ArgumentException is being thrown when attempting to display an Open File Dialog.

Exception Message:   Value does not fall within the expected range.
Method Information:  MS.Internal.AppModel.IShellItem2 GetShellItemForPath(System.String)
Exception Source:    PresentationFramework
Stack Trace
  at MS.Internal.AppModel.ShellUtil.GetShellItemForPath(String path)
  at Microsoft.Win32.FileDialog.PrepareVistaDialog(IFileDialog dialog)
  at Microsoft.Win32.FileDialog.RunVistaDialog(IntPtr hwndOwner)
  at Microsoft.Win32.FileDialog.RunDialog(IntPtr hwndOwner)
  at Microsoft.Win32.CommonDialog.ShowDialog(Window owner)
  ...

The problem is that so far I haven't been able to replicate this in my development environment but I have received several reports from the field that this exception is occurring.

Has anyone seen this before? And most importantly do you know the cause and/or a fix for it other than just simply putting a try/catch around it and instructing the user to try again whatever it is they were trying to do?

In response to a comment, this is the code that opens the dialog (and no, it was not a problem of checking the return type). The exception is thrown from within ShowDialog (see stack trace):

Nullable<bool> result = null;

var dlg = new Microsoft.Win32.OpenFileDialog();
dlg.DefaultExt = ".txt";
dlg.Filter = "Text Files (.txt)|*.txt|All Files|*.*";
dlg.Title = "Open File";
dlg.Multiselect = false;
dlg.InitialDirectory = GetFolderFromConfig("folders.templates");
result = dlg.ShowDialog(Window.GetWindow(this));

if (result == true)
{
    // Invokes another method here..
}

Answer 1

This issue can also occur with non-special directories, such as mapped network drives. In my case, our %HOME% environment variable points to a mapped network drive (Z:). Thus the following code generates the same exception:

Nullable<bool> result = null;

var dlg = new Microsoft.Win32.OpenFileDialog();
dlg.DefaultExt = ".txt";
dlg.Filter = "Text Files (.txt)|*.txt|All Files|*.*";
dlg.Title = "Open File";
dlg.Multiselect = false;
dlg.InitialDirectory = Environment.GetEnvironmentVariable("Home")+@"\.ssh"; // boom
result = dlg.ShowDialog(Window.GetWindow(this));

Solution:

var dlg = new Microsoft.Win32.OpenFileDialog();
dlg.DefaultExt = ".txt";
dlg.Filter = "Text Files (.txt)|*.txt|All Files|*.*";
dlg.Title = "Open File";
dlg.Multiselect = false;
dlg.InitialDirectory = System.IO.Path.GetFullPath(Environment.GetEnvironmentVariable("Home")+@"\.ssh"); // no boom
result = dlg.ShowDialog(Window.GetWindow(this));

Answer 2

This should really go to @Hans Passant as he pointed me in the right direction.

It turns out the problem was trivial to replicate (and fix) on my development computer once I figured out what the problem really was. It turns out that the issue was indeed the InitialDirectory property being set to some odd value. in my case I was able to replicate the issue by setting InitialDirectory to "\\";

Here's the modified code to address the issue:

 try
 {
     result = dlg.ShowDialog(Window.GetWindow(this));
 }
 catch{
     dlg.InitialDirectory = Environment.GetFolderPath(Environment.SpecialFolder.MyComputer);
     result = dlg.ShowDialog(Window.GetWindow(this));
 }

Answer 3

      ///<summary>
      /// Tries to handle inability of user to access file dialog folder
      /// by using other folder. Shows meaningful message to 
      /// user for action on failure.
      ///</summary>
      private bool? ShowDialogSafe()
      {
        try
        {
            return dlg.ShowDialog(Window.GetWindow(this));
        }
        // reacts on rare case of bad default folder, filter only folder related excepions
        catch (Exception handledEx) when (IsInitialDirectoryAccessError(handledEx))
        {
            var original = dlg.InitialDirectory;
            var possible = Environment.GetFolderPath(Environment.SpecialFolder.Personal);// hope user has access to his own, may try Desktop
            try
            {
                dlg.InitialDirectory = possible;
                return FileDialog.ShowDialog(Window.GetWindow(this));
            }
            catch (Exception ex) when (IsInitialDirectoryAccessError(ex))
            {
                var message = string.Format("Failed to access directories '{0}' and '{1}'. Please contact system administrator.", original, possible);
                throw new IOException(message, ex);
            }
        }
    }

    /// <summary>
    /// see GetShellItemForPath(string path) http://referencesource.microsoft.com/#PresentationFramework/src/Framework/MS/Internal/AppModel/ShellProvider.cs,f0a8bc5f6e7b1503,references
    /// System.IO.FileNotFoundException: 'The network name cannot be found. (Exception from HRESULT: 0x80070043)' - no such share exsits
    /// "Access is denied. (Exception from HRESULT: 0x80070005 (E_ACCESSDENIED))"}  System.UnauthorizedAccessException - folder is forbidden
    /// System.ArgumentException: 'Value does not fall within the expected range.' - badly formatted path
    /// </summary>
    /// <param name="handledEx"></param>
    /// <returns></returns>
    private static bool IsInitialDirectoryAccessError(Exception handledEx)
        => handledEx is IOException || handledEx is UnauthorizedAccessException || handledEx is ArgumentException;