Invalid Data Exception when using ExcelDataReader

Question

I have a program that reads Excel file using ExcelDataReader.dll.
Everything was perfect until I moved the file reading to a new task:

Stream output = new MemoryStream();
httpRequest.Files[0].InputStream.CopyToAsync(output);
ImportDataWriter importDatawRiter = new ImportDataWriter(authenticationInfo);
Task.Run(() => importDatawRiter.ImportFile(output));

ImportLine Code:

public ImportResult ImportFile(Stream fs)
{
        IExcelDataReader reader = ExcelReaderFactory.CreateOpenXmlReader(fs);
}

Now this line:

IExcelDataReader reader = ExcelReaderFactory.CreateOpenXmlReader(fs);

causes an Exception:

An exception of type 'System.IO.InvalidDataException' occurred in System.IO.Compression.dll but was not handled in user code

Message:

End of Central Directory record could not be found.

The Exception occurs from the second time I call the function.

What Can Be The Problem?

@Ctznkane525 no. I use first and second time exactly the same file. both times xlsx. — Rachel Fishbein
– Rachel Fishbein, Commented Jan 25, 2018 at 13:13
You aren't awaiting .CopyToAsync(output);. So the code goes when the copy hasn't finished — Camilo Terevinto
– Camilo Terevinto, Commented Jan 25, 2018 at 13:13
@CamiloTerevinto That was the problem. Please Insert your Comment as Answer, I will mark it as the correct answer. — Rachel Fishbein
– Rachel Fishbein, Commented Jan 25, 2018 at 13:26

Camilo Terevinto · Accepted Answer · 2018-01-25 13:30:10Z

3

The problem is that you are not waiting for the Copy task to finish, so when you get to read the MemoryStream, it is not full (it may even be completely empty), so, change your code to:

Stream output = new MemoryStream();
await httpRequest.Files[0].InputStream.CopyToAsync(output);
^^^^^
ImportDataWriter importDatawRiter = new ImportDataWriter(authenticationInfo);
Task.Run(() => importDatawRiter.ImportFile(output));

And, unless ImportFile is a fire-and-forget action, I'd suggest you to use

await Task.Run(() => importDatawRiter.ImportFile(output));

answered Jan 25, 2018 at 13:30

Camilo Terevinto

32.2k7 gold badges95 silver badges127 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Invalid Data Exception when using ExcelDataReader

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related