CODEWITHSUNDEEP
c#windows-8
CognitiveDesire
CognitiveDesire

Reputation: 784

FileIO in win 8 app

I have to log my application events and exceptions in a file in win 8 app in documents folder

Windows.Storage.StorageFolder localFolder = KnownFolders.DocumentsLibrary;

The problem is when I call WriteToFile function one after other there is an access is denied exception because the file is still being used. Is there a way to make this work

public async void WriteToFile(string log)
            {
                try
                {

                    StorageFile sampleFile = await localFolder.CreateFileAsync("dataFile.txt", CreationCollisionOption.OpenIfExists);
                    //StorageFile sampleFile = await localFolder.GetFileAsync("dataFile.txt");
                    IRandomAccessStream writeStream = await sampleFile.OpenAsync(FileAccessMode.ReadWrite);
                    IOutputStream outputStream = writeStream.GetOutputStreamAt(writeStream.Size);
                    DataWriter dataWriter = new DataWriter(outputStream);
                    dataWriter.WriteString(log);

                    dataWriter.StoreAsync().AsTask().Wait();
                    outputStream.FlushAsync().AsTask().Wait();

                }
                finally
                {

                }

            }

Upvotes: 1

Views: 1117

Answers (2)

alfah
alfah

Reputation: 2085

you could try the following

dataWriter.Dispose();
await outputStream.FlushAsync();
await stream.FlushAsync();

Upvotes: 0

Verni
Verni

Reputation: 211

Looks like you forgot to close the Stream after write operation. The file will be locked until you close the Stream.

dataWriter.Close();

MSDN Link

or use the "using" Keyword like this:

 using(DataWriter dataWriter = new DataWriter(outputStream)) 
 {
       dataWriter.WriteString(log);
       dataWriter.StoreAsync().AsTask().Wait(); 
 }

It's a good idea to check if the file is locked, so you didn't get an exception.

How to Check for locked file

Greetings, hope it helps

Upvotes: 2

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