来自绝对文件路径的UWP中的ReadLinesAsync

Question

I get error

The filename, directory name, or volume label syntax is incorrect. (Exception from HRESULT: 0x8007007B)

My code is

public async void ReadFile()
    {     
        var path = @"F:\VS\WriteLines.xls";
        var folder = Windows.ApplicationModel.Package.Current.InstalledLocation;

        var file = await folder.GetFileAsync(path);
        var readFile = await Windows.Storage.FileIO.ReadLinesAsync(file);
        foreach (var line in readFile.OrderBy(line =>
        {
            int lineNo;
            var success = int.TryParse(line.Split(';')[4], out lineNo);
            if (success) return lineNo;
            return int.MaxValue;
        }))
        {
            itemsControl.Items.Add(line);
        }
    }

The error shows up at var file = await folder.GetFileAsync(path);

Answer 1

You cannot read a file from an arbitrary location on disk in a UWP App. There are a couple of ways you can still accomplish your task:

1. You can add the WriteLines.xls file to your project and set it's build action to Content and Copy to output Directory to Copy if newer . You can then access the file with the code you have by simply replacing the "path" value to:

var path = @"WriteLines.xls"

More details here

2. If you need to be able to read any files from disk, you need to either use a FilePicker to select the file or copy the file in the Documents Folder and change the folder to:

var folder = KnownFolders.DocumentsLibrary;

More details here

Answer 2

You are asking for file with absolute path from application's local folder - hence it throws that error as you provide path that includes drive name.

In general UWP is very restrictive on where/how you can get files from - I don't think you can get it from absolute path in the sample (app needs more permissions to get to similar places). You can try StorageFile.GetFileFromPathAsync .

Detailed info on locations app can access - UWP apps on Windows 10: File access permissions .