How to read open excel file at C#

Question

I want to read already open excel file with C#. I am using this method but it can't read the excel file while the file is open in Microsoft excel.

FileStream stream = File.Open("myfile.xlsx", FileMode.Open, FileAccess.Read);

It gives IOException: The process cannot access the file 'myfile.xlsx' because it is being used by another process.

I hope you understands what I mean. I want to keep excel file open and while file is open at Microsoft excel i want to read it from C#. I am using C# net framework 4.0

You can't if the file is opened by on other process – Harold Sota Feb 14 '11 at 12:21 — Harold Sota, Feb 14 '11 at 12:21
Are you sure that there isn't any way to achive that ? – Furkan Gözükara Feb 14 '11 at 12:35 — Furkan Gözükara, Feb 14 '11 at 12:35
How about: http://support.microsoft.com/kb/316126 – Fionnuala Feb 14 '11 at 12:40 — Fionnuala, Feb 14 '11 at 12:40
See here: http://stackoverflow.com/a/898017/48082 – Cheeso Jul 02 '14 at 02:01 — Cheeso, Jul 02 '14 at 02:01

score 25 · Answer 1 · edited May 23 '17 at 11:46

25

You need to open it with FileShare.ReadWrite:

FileStream stream = File.Open("myfile.xlsx", FileMode.Open, FileAccess.Read, FileShare.ReadWrite);

See this answer.

edited May 23 '17 at 11:46

Community

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answered Feb 20 '12 at 05:09

splintor

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This is not working for me still getting the same error message. – jcubero Oct 20 '15 at 18:31
This works great for local files. However, it does not work for Excel files on OneDrive, even when Auto Save is disabled. – PeterB Jul 26 '19 at 13:54

score 7 · Accepted Answer · answered Feb 14 '11 at 12:59

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I think you can still copy the file while excel has it open, so you could make a copy of the file and then open that. Just make sure you clean up after yourself when you are done with the copy.

answered Feb 14 '11 at 12:59

John Koerner

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score 3 · Answer 3 · answered Feb 14 '11 at 12:50

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You could use the Interop library to use the already opened instance of Excel.

oExcel == (Excel.Application) System.Runtime.InteropServices.Marshal.GetActiveObject("Excel.Application")

answered Feb 14 '11 at 12:50

Koen

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what namespace do i need for this ? – Furkan Gözükara Feb 14 '11 at 13:03
Microsoft.Office.Interop For more information just google for "Excel automation". Lots of info on the net ;-) – Koen Feb 14 '11 at 15:24
Noticed the other answer. Copying the file is indeed a much better way here ;-) – Koen Feb 14 '11 at 15:34

score 1 · Answer 4 · answered Feb 14 '11 at 12:46

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You can try the File.Open with a fourth parameter - fileShare.

FileStream stream = File.Open("myfile.xlsx", FileMode.Open, FileAccess.Read, FileShare.Read);

You may need to specify write access also.

answered Feb 14 '11 at 12:46

doobop

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That's because you need to open it with FileShare.ReadWrite - see http://stackoverflow.com/questions/897796/how-do-i-open-an-already-opened-file-with-a-net-streamreader/898017#898017 – splintor Feb 20 '12 at 04:56

score 0 · Answer 5 · answered Oct 28 '12 at 20:14

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To open the same file more than once at the same time, it needs to be opened in shared mode.

Hope this may help others.

answered Oct 28 '12 at 20:14

Farjad

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score 0 · Answer 6 · edited Feb 14 '11 at 12:47

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To ensure that correct opening and closing of the file please look at using the c# using statements

using (FileStream stream = File.Open("myfile.xlsx", FileMode.Open, FileAccess.Read)) 
{

}

edited Feb 14 '11 at 12:47

Devendra D. Chavan

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answered Feb 14 '11 at 12:29

Somedeveloper

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did you understand what i am asking ? i don't want to close excel and while file is open at microsoft office excel i want to read it to my C# – Furkan Gözükara Feb 14 '11 at 12:35

How to read open excel file at C#

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