Easiest way to read text file which is locked by another application

c# filestream text-files
Benjol picture Benjol · Sep 7, 2009 · Viewed 16.9k times · Source

I've been using File.ReadAllText() to open a CSV file, but every time I forget to close the file in Excel, the application throws an exception because it can't get access to the file.

(Seems crazy to me, I mean the READ in ReadAllText seems pretty clear)

I know that there is File.Open with all the bells and whistles, but is there an 'intermediate' method which doesn't involve messing around with buffers and char arrays?

Answer

Noldorin picture Noldorin · Sep 7, 2009

I think you just want the following:

using (var fileStream = new FileStream("foo.bar", FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
using (var textReader = new StreamReader(fileStream))
{
    var content = textReader.ReadToEnd();
}

The FileAccess.Read parameter is what is important, to indicate that you only want to read the file. Of course, even to do this, the file must have been opened by Excel in read-share mode (see the FileShare enum in .NET). I haven't tested, so I can't guarantee that Excel does this, though I would expect it does.

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