Universal App FolderPicker System.Runtime.InteropServices.COMException

Question

I'm trying to make a universal app which merely opens a folder (like a shortcut) but allows for the new start tile design with custom color and bigger icon.

When I open the FolderPicker to give the application access to the directory, I get an error, and I have no idea why.

System.Runtime.InteropServices.COMException

Please assist.

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices.WindowsRuntime;
using System.Threading.Tasks;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.Storage;
using Windows.Storage.Pickers;
using Windows.Storage.AccessCache;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Navigation;

// The Blank Page item template is documented at http://go.microsoft.com/fwlink/?LinkId=402352&clcid=0x409

namespace App1
{
    /// <summary>
    /// An empty page that can be used on its own or navigated to within a Frame.
    /// </summary>
    public sealed partial class MainPage : Page
    {
        public MainPage()
        {
            this.InitializeComponent();


            doPickFile();
            //Application.Current.Exit();
        }

        private async void doPickFile()
        {

            bool folderAdded = StorageApplicationPermissions.FutureAccessList.ContainsItem("\\\\server\\share$");

            if (!folderAdded)
            {
                var openPicker = new FolderPicker() { SuggestedStartLocation = PickerLocationId.PicturesLibrary  };
                StorageFolder folder = await openPicker.PickSingleFolderAsync();
                if (folder.Path == "\\\\server\\share$")
                {
                    StorageApplicationPermissions.FutureAccessList.AddOrReplace("PickedFolderToken", folder);
                }
            }
            else
            {
                StorageFolder pickedFolder = await StorageApplicationPermissions.FutureAccessList.GetFolderAsync("\\\\server\\share$");
                await Windows.System.Launcher.LaunchFolderAsync(pickedFolder);
            }
        }
    }
}

Specifically the debugger stops at the line: StorageFolder folder = await openPicker.PickSingleFolderAsync();

have you tried it without using the async, await? If not, first try without async,await! most of the com exception getting thrown by the threads or you can say not using the threads in a proper way — Dirty Developer, Nov 07 '16 at 00:39

Simon · Answer 1 · 2019-03-22T17:44:35.673

10

You have to add a FileTypeFilter.

    var openPicker = new FolderPicker() { SuggestedStartLocation = PickerLocationId.PicturesLibrary }; 
    openPicker.FileTypeFilter.Add("*");
    StorageFolder folder = await openPicker.PickSingleFolderAsync();

There is also an official Microsoft sample which shows this.

The strange thing about it: you could also use FileTypeFilter.Add(".anytext") instead of FileTypeFilter.Add("*") since the current FolderPicker in Windows does not actually filter for file types. Therefore I cannot explain why you have to do this.

edited Mar 22 '19 at 17:44

answered Feb 26 '17 at 10:03

Simon

165
1
8

If you have a new question, please ask it by clicking the [Ask Question](/questions/ask) button. Include a link to this question if it helps provide context. – Donald Duck Feb 26 '17 at 10:19
1

Sorry that I didn't make this clear, but it _is_ actually an answer to the question. – Simon Feb 26 '17 at 10:58
Edited my answer accordingly. – Simon Feb 26 '17 at 11:15
Microsoft documentation uses `picker.FileTypeFilter.Add("*")` in [this sample](https://learn.microsoft.com/en-us/windows/uwp/files/quickstart-using-file-and-folder-pickers#pick-a-folder-complete-code-listing) – ghord Mar 21 '19 at 16:56
@ghord Thanks for the hint. I changed this in my answer. – Simon Mar 22 '19 at 17:34

Universal App FolderPicker System.Runtime.InteropServices.COMException

1 Answers1