Do I need to close the file after calling ReadAllText?

Question

I do the following:

if (File.Exists(filePath)) { string base64 = File.ReadAllText(filePath); return new ImageContentDTO { ImageContentGuid = imageContentGuid, Base64Data = base64 }; } 

This works great. I want to ask if I need to close a file or something like that after I read it. And if so, how?

Answer 1

No, you do not need to explicitly close the file, File.ReadAllText will take care of this for you.

The documentation contains this information very clearly:

This method opens the file, reads each line of the file, and then adds each line as a line item. Then it closes the file.
[...]
This file descriptor is guaranteed to close with this method, even if exceptions occur.

Answer 2

You do not need to close anything when using File.ReadAllText , since the underling thread reader closes implicitly.

MSDN: File.ReadAllText

Opens a text file, reads all lines of the file, and closes the file .

Here's the implementation in .NET 4 (ILSpy):

 string result; using (StreamReader streamReader = new StreamReader(path, encoding)) { result = streamReader.ReadToEnd(); } return result; 

The using statement provides a StreamReader (even if an error StreamReader ), which also closes it.

Answer 3

I know that this question has been answered, and it has been almost a year, but for those who are looking for and reading this question, I would like to suggest that you close the file after it is completed, or at least conduct an investigation, for example, mine The answer shows.

I am not a programming specialist, but recently I came across this situation.

I created the WinForms C # program and used File.ReadAllText to copy text to a string. Subsequently, I tried to delete the file directly from the folder, and not through the program, but I received an error message that the file is still open in another program. Then I stopped the program from starting and was able to delete the file.

This is my experience in Visual Studio 2012 Ultimate. Could do something else, but what it did for me.

When I used StreamReader.ReadToEnd , then StreamReader.Close in the same file, I had no problems deleting the file during program startup.

Answer 4

You need to close only IDisposable instances, usually using, for example:

  // StreamReader is IDisposable and should be Closed/Disposed // either explicitly or by using using (StreamReader sr = new StreamReader(filePath)) { String base64 = sr.ReadToEnd(); ... } 

since you don't have an instance of IDisposable in your code (File.ReadAllText returns a string that is not IDisposable), you have nothing to close / delete