Develop Reference

Reading/Writing RichEditBox (.rtf) files without using picker (C# - Visual Studio - UWP)

I am struggling to create my first UWP program in C#. I have run into a problem with reading/writing .rtf files and have not been able to work out a solution nor find one in the forums.
My program is an application for reading and writing a daily journal. The daily journal entries are displayed and edited in a RichEditBox. Next to the RichEditBox is a CalendarDatePicker.
When the CalendarDatePicker value changes, the program creates a file name based on the CalendarDatePicker date. For example, if the CalendarDatePicker's value was 7/22/2018, my program would turn that into the following file name: "2018_7_22.rtf" and then assign that to a string named fileName.
All of the above is working as desired. Here is the problem I am having:
When the value of the CalendarDatePicker changes, the program is supposed to immediately load the .rtf file (if it exists) from storage into the RichEditBox. And, when I press the SAVE button, the program is
supposed to save the RichEditBox contents to storage. Both reading and writing the file is supposed to
use the name derived from the CalendarDatePicker value rather than opening up a picker for either
opening or saving the file.
I have not been able to find any documentation about how to read and write a .rtf file for the RichEditBox without using a picker. I do not want to use a picker because I want that the given journal entry can only be read or written according to the file name that is based on the current value of the CalendarDatePicker.
Here is what I am trying to do:
String filePath = Windows.Storage.ApplicationData.Current.LocalFolder.toString;
// this returns error: "cannot convert method group 'ToString' to non-delegate type string"
String fileName = "2018_22_7.rtf"
// this is an example of a string my program would create according to the CalendarDatePicker's value.
At the end of my question is the code from the RichEditBox documentation. I want do away with the portion that uses the picker and replace the following line:
Windows.Storage.StorageFile file = await savePicker.PickSaveFileAsync();
with:
Windows.Storage.StorageFile file = filePath + fileName;
Is it possible to do this or am I forced to use a picker with the RichEditBox?
I will deeply appreciate any help I can get in solving this problem. I am
melting from frustration! Thank you!
Here is the code from the RichEditBox documentation:
private async void SaveButton_Click(object sender, RoutedEventArgs e)
{
Windows.Storage.Pickers.FileSavePicker savePicker = new Windows.Storage.Pickers.FileSavePicker();
savePicker.SuggestedStartLocation = Windows.Storage.Pickers.PickerLocationId.DocumentsLibrary;
// Dropdown of file types the user can save the file as
savePicker.FileTypeChoices.Add("Rich Text", new List<string>() { ".rtf" });
// Default file name if the user does not type one in or select a file to replace
savePicker.SuggestedFileName = "New Document";
Windows.Storage.StorageFile file = await savePicker.PickSaveFileAsync();
if (file != null)
{
// Prevent updates to the remote version of the file until we
// finish making changes and call CompleteUpdatesAsync.
Windows.Storage.CachedFileManager.DeferUpdates(file);
// write to file
Windows.Storage.Streams.IRandomAccessStream randAccStream =
await file.OpenAsync(Windows.Storage.FileAccessMode.ReadWrite);
editor.Document.SaveToStream(Windows.UI.Text.TextGetOptions.FormatRtf, randAccStream);
// Let Windows know that we're finished changing the file so the
// other app can update the remote version of the file.
Windows.Storage.Provider.FileUpdateStatus status = await Windows.Storage.CachedFileManager.CompleteUpdatesAsync(file);
if (status != Windows.Storage.Provider.FileUpdateStatus.Complete)
{
Windows.UI.Popups.MessageDialog errorBox =
new Windows.UI.Popups.MessageDialog("File " + file.Name + " couldn't be saved.");
await errorBox.ShowAsync();
}
}
}

Universal Windows Apps (apps) can access certain file system locations by default.
Before window version 17134, if you don't want use a picker to access the file, your UWP app only can access the files in the Application install directory, Application data locations, Removable devices and some Locations that UWP apps can access with specific Capability such as the Music and Pictures Libraries. But you can not write into the Application install directory. In this case, you can try to save the file in above location except the Application install directory. Such as the Application data locations then you can create and get the file using the following code. Please see the File access permissions for more details.
StorageFolder localFolder = ApplicationData.Current.LocalFolder;
//Createa file
StorageFile fileToSave = await localFolder.CreateFileAsync("YourFileName");
//Get file
StorageFile file = await localFolder.GetFileAsync("YourFileName");
If your app target on version 17134 and later, you can access all files that the user has access to using the broadFileSystemAccess Capability, this capability works for APIs in the Windows.Storage namespace, you can get the file using the path as following code, here is a sample.
StorageFolder folder = await StorageFolder.GetFolderFromPathAsync(path);

UWP . Copy file from FileOpenPicker to localstorage

FileOpenPicker picker = new FileOpenPicker();
picker.ViewMode = PickerViewMode.Thumbnail;
picker.SuggestedStartLocation = PickerLocationId.ComputerFolder;
picker.FileTypeFilter.Add(".txt");
A user chooses a file to open. How can I store/copy/save that file to localstorage for future use, so every time the app opens, it picks automatically that file?

After the user opens the file using the FileOpenPicker you can "cache" access to it using StorageApplicationPermissions API.
Once you have the StorageFile you want to open automatically, you can "cache" your access to it using the following code:
string token = StorageApplicationPermissions.FutureAccessList.Add( file );
What you get back is a string token, which you can save for example in the app settings. Next time the app is opened, you can retrieve the file again using the following code:
StorageFile file =
await StorageApplicationPermissions.FutureAccessList.GetFileAsync(token);
Note that this API has limitation of at most 1000 items stored, so if you expect that more could be added, you will have to ensure the older files are removed otherwise you would not be able to add new files.
There is also alternative - StorageApplicationPermissions.MostRecentlyUsedList which you can use the same way as the FutureAccessList, but it has the advantage of automatically managing the list. It can store up to 25 items, but it is able to automatically remove the oldest ones when not needed anymore.
Also note, that this APIs can cache access not only to files but also to folders (StorageFolder).
Copying the file to AppData folder
If you just want to create a local copy of the picked file, you can copy it to the local folder of the app.
var file = await picker.PickSingleFileAsync();
if ( file != null )
{
await file.CopyAsync( ApplicationData.Current.LocalFolder );
}

StorageFile file = await openPicker.PickSingleFileAsync();
if (file != null)
{
var yourPath = file.Path;
}
but It won't work as you expect. But remember you can't open file from location you (your app) don't have access to.
edit: yeah, I see in comments that I have missed some part of the qestion ;)
the easiest way to store the information for future re-use would be propably to use LocalSettings
https://msdn.microsoft.com/library/windows/apps/windows.storage.applicationdata.localsettings.aspx
(sorry for the link, but there is no use in copying info from there)

You could:
1) Store the file name in your project settings;
YourNameSpace.Properties.Settings.fileToLoad;
2) write the file name in a local file (look at TextWriter namespace);
3) store the file name in your database if your application is data-driven
... and others.
I am presuming here that you're using WinForms or Console app. If you are using a webForm, you would need to store the file name in a cookie so you could attach the right file to the right user before they log in or give you credenstials. For Webforms, then, look into the use of cookies.

Just to add to the above suggestions, following example from Official Microsoft document shows how to Store file for future access:
var openPicker = new FileOpenPicker();
StorageFile file = await openPicker.PickSingleFileAsync();
// Process picked file
if (file != null)
{
// Store file for future access
Windows.Storage.AccessCache.StorageApplicationPermissions.FutureAccessList.Add(file);
}
else
{
// The user didn't pick a file
}

How to display an image from a network folder or local drive in a Windows Universal App

I'm having trouble displaying an jpg in an Image control in a Windows Universal App. (I had the same problem trying to create a Windows 8 Store app as well)
I have a simple form with an Image control on it. All I want to do is be able to open images in a folder on my local drive or a network drive on my local network and display them. But I am not having any luck. The only thing I get is E_NETWORK_ERROR, with no additional information.
I assume it probably has something to do with security, but surely there must be a setting or permission to allow me to do it. I tried enabling Private Networks in the Capabilities tab of the manifest, but that didn't help. I don't see anything in Declarations that sounds like what I need.
I know UWP apps are somewhat sandboxed, but if you can't even access local files, what good are they?
Here is a sample of code I have tried. I've done other iterations as well, but they all have the same end result.
Xaml:
<Image Name="Image1"/>
Code behind:
public LoadImage()
{
var bitmap = new BitmapImage();
bitmap.ImageFailed += Bitmap_ImageFailed;
bitmap.UriSource = new Uri(#"D:\Users\Steve\Documents\SomeImage.JPG", UriKind.Absolute);
Image1.Source = bitmap;
}
private void Bitmap_ImageFailed(object sender, ExceptionRoutedEventArgs e)
{
Debug.Write(e.ErrorMessage);
}
When I run it, I end up in the Bitmap_ImageFailed event and the ErrorMessage property is simply "E_NETWORK_ERROR", and nothing is displayed in the Image. Not very helpful.
What am I missing? It has to be something simple and obvious that I am overlooking.
Update:
Thanks to all the suggestions here I was able to get it going. The part I was failing to get through my skull was that you can't just give it a folder and expect it to read a file, even as a "quick & dirty test". You have to go through "proper channels" to get there. I pieced it all together and came up with this example which displays the first image in the selected folder:
private async void Button_Click(object sender, RoutedEventArgs e)
{
FolderPicker folderPicker = new FolderPicker();
folderPicker.SuggestedStartLocation = PickerLocationId.Desktop;
folderPicker.FileTypeFilter.Add(".jpg");
folderPicker.FileTypeFilter.Add(".tif");
folderPicker.FileTypeFilter.Add(".png");
StorageFolder folder = await folderPicker.PickSingleFolderAsync();
if (folder != null)
{
StorageApplicationPermissions.FutureAccessList.AddOrReplace("PickedFolderToken", folder);
var files = await folder.GetFilesAsync();
var bitmap = new BitmapImage();
bitmap.ImageFailed += Bitmap_ImageFailed;
var stream = await files.First().OpenReadAsync();
await bitmap.SetSourceAsync(stream);
Image1.Source = bitmap;
}
}
In addition, I had to add the file types for .jpg, .tif and .png as well as File Open Picker to the Declarations.

You can figure out all necessary information in MSDN article File access permissions
In addition to the default locations, an app can access additional files and folders by declaring capabilities in the app manifest (see App capability declarations), or by calling a file picker to let the user pick files and folders for the app to access (see Open files and folders with a picker).
So if you want to read a file from users document folder you need to update your applications AppXManifest to request the Document Library Access capability.
You also need to update your AppXManifest by declaring what file type(s) you want to access. Then, even with access to the folders, you only have access to a limited set of file types. You have to specify supported files types on Declarations tab
I set a new file type (.txt) and let it role from there. And code example
async void Button_Click_2(object sender, RoutedEventArgs e)
{
var _Name = "HelloWorld.txt";
var _Folder = KnownFolders.DocumentsLibrary;
var _Option = Windows.Storage.CreationCollisionOption.ReplaceExisting;
// create file
var _File = await _Folder.CreateFileAsync(_Name, _Option);
// write content
var _WriteThis = "Hello world!";
await Windows.Storage.FileIO.WriteTextAsync(_File, _WriteThis);
// acquire file
try { _File = await _Folder.GetFileAsync(_Name); }
catch (FileNotFoundException) { /* TODO */ }
// read content
var _Content = await FileIO.ReadTextAsync(_File);
await new Windows.UI.Popups.MessageDialog(_Content).ShowAsync();
}

Access all files in folder from FileActivated file

I write a Windows 10 Universal App like the default Photo App in C#. The Photo App allows to show all images in the directory where the user opened the file with the Photo App. But when the user opened a file with my App I get only the FileActivatedEventArgs with allows to display the file the user opened. I found no solution to show the user the other files from the directory of this file too. I think the problem is to get the permission to access that files because when the folder of the file is in the picture library it works. But the Windows Photo App can this everywhere so I think there must be a solution ...
Edit: I have tried to extract a very simple sample code from my project that show the relevant part in only a few lines of code
public static async Task<BitmapImage> LoadImage(StorageFile file)
{
BitmapImage bitmapImage = new BitmapImage();
FileRandomAccessStream stream = (FileRandomAccessStream)await file.OpenAsync(FileAccessMode.Read);
bitmapImage.SetSource(stream);
return bitmapImage;
}
private async void setImages(FileActivatedEventArgs args)
{
StorageFile si = (StorageFile)App.args.Files.First();
StorageFolder st = await si.GetParentAsync();
StorageApplicationPermissions.FutureAccessList.Add(st);
IReadOnlyList<StorageFile> sflist = await st.GetFilesAsync();
foreach (StorageFile sf in sflist)
{
imageList.Add(await LoadImage(sf));
}
}

Yes, you have NO access rights for the folder. In this case, GetParentAsync() may fall.
You should use "IFileActivatedEventArgsWithNeighboringFiles" to parse the neighboring files. By using this interface, OS's File Broker process passed the neighboring files to you.
https://msdn.microsoft.com/en-us/library/windows/apps/windows.applicationmodel.activation.ifileactivatedeventargswithneighboringfiles
Note - This API was added from Win8.1. And, Win8.0 ver of Photo app can't show the neighboring files when it was activated by FileActivated. Win8.1 ver of Photo app may use this API.

You may need to add the following to the Package.appxmanifest file so you can access the Pictures Library then you should be able to get this to work:
<Capabilities>
<uap:Capability Name="picturesLibrary"/>
</Capabilities>

Windows Phone 8: Share an Image from Assets folder

I want to use ShareMediaTask to share an images inside my application's Assets folder, here's the code I use:
private async void MenuShare_Click(object sender, EventArgs e)
{
StorageFolder installationFolder = Windows.ApplicationModel.Package.Current.InstalledLocation;
StorageFile file = await installationFolder.GetFileAsync(#"Assets\shanghaimetro-1.png");
var shareMediaTask = new ShareMediaTask
{
FilePath = file.Path
};
shareMediaTask.Show();
}
But the standard Windows Phone sharing screen never appers. It just go back to the page where I came after click the share button.
In debug mode, I am able to see the file.Path is:
C:\Data\Programs\{E6357D2C-2888-448E-8990-4C8D37510514}\Install\Assets\shanghaimetro-1.png
It should be correct path.
Is there anything wrong in this code? How can I make it working?

You need to save the photo to the MediaLibrary and then use the GetPath() extension method (Microsoft.Xna.Framework.Media.PhoneExtensions namespace) to retrieve the path. Assign this path to the FilePath property