Develop Reference

How to upload an audio file with ID3 tags into an application using C# and visual studio

I am currently working on code to pull an mp3 file from a user's computer and upload it into a music library application that I am creating in visual studio UWP using C#. It needs to be able to pull the ID3 tags for artist, title, and album, as these will all have to be referenced on the actual library page, where the music will be sorted accordingly.
The following code is what I have so far, and I am currently stuck on what else to write just to upload the file into the music library portion of my app with the ID3 tags:
//Uploading Music File Button
private async void UploadButton_Click(object sender, RoutedEventArgs e)
{
//Opening User's personal Music Library to select files
var picker = new Windows.Storage.Pickers.FileOpenPicker
{
ViewMode = Windows.Storage.Pickers.PickerViewMode.Thumbnail,
SuggestedStartLocation =
Windows.Storage.Pickers.PickerLocationId.MusicLibrary
};
//Accepted file type = mp3 (only mp3 files display for user selection)
picker.FileTypeFilter.Add(".mp3");
StorageFile file = await picker.PickSingleFileAsync();
if (file != null)
{
// Application now has read/write access to the picked file
//Storing File for future use
Windows.Storage.AccessCache.StorageApplicationPermissions.FutureAccessList.Add(file);
// Open a stream for the selected file.
// The 'using' block ensures the stream is disposed
// after the music is loaded.
IRandomAccessStream fileStream =
await file.OpenAsync(FileAccessMode.ReadWrite);
}
}
I am very new to all this, so I may be missing some very obvious things in this code. I have checked into various tutorials and examples, but none of them provide the exact fit I'm looking for or are half done. Thank you for taking the time to read my code and offer any advice/suggestions.

How to upload an audio file with ID3 tags into an application using C# and visual studio
For accessing audio metadata, you could use GetMusicPropertiesAsync method to get audio file's album artist title MusicProperties property.
try
{
StorageFile file = rootPage.sampleFile;
if (file != null)
{
StringBuilder outputText = new StringBuilder();
// Get music properties
MusicProperties musicProperties = await file.Properties.GetMusicPropertiesAsync();
outputText.AppendLine("Album: " + musicProperties.Album);
outputText.AppendLine("Rating: " + musicProperties.Rating);
}
}
// Handle errors with catch blocks
catch (FileNotFoundException)
{
// For example, handle a file not found error
}
For uploading the audio file to server, you could use BackgroundTransfer api. and this is code sample you could refer to. And you could also you HttpClient API to post your file stream.

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
}

Writing a JSON (or TXT) file in WPF C#

I have been trying to make sense of this http://msdn.microsoft.com/en-us/library/sfezx97z.aspx which uses the SaveFileDialog, but it is hard for me to understand. I have the following code:
FileInfo existingFile = new FileInfo("C:\\Users\\cle1394\\Desktop\\Apple Foreign Tax Payment Sample Layout Proposed - Sample Data.xlsx");
ConsoleApplication2.Program.ExcelData data = ConsoleApplication2.Program.GetExcelData(existingFile);
var json = new JavaScriptSerializer().Serialize(data);
How can I output the contents of json to a .json or .txt file?
I would like to let the user either see a link/ button to click to download/ save the file to a location on their computer, or, simply display the save file dialog box so that they can save the file to a location on their computer.
EDIT (to let OP comment on what parts are not clear):
SaveFileDialog saveFileDialog1 = new SaveFileDialog();
saveFileDialog1.ShowDialog();
if(saveFileDialog1.FileName != "")
{
File.WriteAllText(saveFileDialog1.FileName,json);
}

You are looking for this, then:
File.WriteAllText(#"c:\some\path\json.txt",json);
And note that it will save the file using UTF8-encoding without a Byte Order Mark. If you need the BOM, you need to use the File.WriteAllText(path, content, Enconding);
See here.
Update - adding sample with SaveFileDialog:
if(!string.IsNullOrEmpty(saveFileDialog.FileName))
{
//saveFileDialog.FileName should contain the full path
//according to the documentation: http://msdn.microsoft.com/en-us/library/system.windows.forms.filedialog.filename.aspx
File.WriteAllText(saveFileDialog.FileName,json);
}

How to change the DateCreated on a StorageFile?

Per http://msdn.microsoft.com/en-us/library/windows/apps/windows.storage.storagefile.datecreated.aspx , StorageFile.DateCreated is read-only.
On the desktop, I can do:
IStorageFile file = ...
DateTime date = ...
BasicProperties props = await file.GetBasicPropertiesAsync();
var changes = new List<KeyValuePair<string,object>>();
changes.Add(new KeyValuePair<string, object>("System.DateCreated", date));
await props.SavePropertiesAsync(changes);
but on WP8, BasicProperties.SavePropertiesAsync isn't implemented.
Is there some other way to do this?

One way would be to take the date created and use ApplicationData.LocalSettings to store the file path and the date created. The risk being that you have to make sure the value is updated everytime you create a file.
Otherwise you could use moveAndReplaceAsync to move the file and reset the date created.
You could also store the values in your own secondary file or database, but that would require extra IO on every file read. (You have to open two files to get at the file contents and the 'date created').