Will an anonymous StreamReader close automatically?

I've found the following code in a project I'm working on and I'm curious to know if it can be written more succinctly.

using (var stream = new FileStream(CustomSettingsFile.FullName, FileMode.Open, FileAccess.Read))
{
    using (var reader = new StreamReader(stream))
    {
        var data = reader.ReadToEnd();
    }
}

Firstly, what's the benefit of using FileStream? I understand that StreamReader can take a file path directly.

using (var reader = new StreamReader(CustomSettingsFile.FullName))
{
    var data = reader.ReadToEnd();
}

Secondly, if I'm only using the reader once, can't I just anonymize it and omit the using?

var data = new StreamReader(CustomSettingsFile.FullName).ReadToEnd();

> I'm curious to know if it can be written more succinctly.

First thing you can do in this specific case is to omit extra curly braces:

using (var stream = new FileStream(CustomSettingsFile.FullName, FileMode.Open, FileAccess.Read))
using (var reader = new StreamReader(stream))
{
    var data = reader.ReadToEnd();
}

> Firstly, what's the benefit of using FileStream? I understand that StreamReader can take a file path directly.

Based on the current implementation none, except for explicitly specifying the FileMode and FileAccess, though as far as I can see StreamReader will use the same defaults.

> Secondly, if I'm only using the reader once, can't I just anonymize it and omit the using?

No. You need to deterministically free the unmanaged resources when you have finished using them. General rule of thumb: If something implements IDisposable then it should be disposed (for example via using which handles exceptions).

Note that since C# 8.0 you can leverage using declarations in some cases, which will call dispose at the end of current scope:

using var reader = new StreamReader(CustomSettingsFile.FullName);
var data = reader.ReadToEnd();

Also in case when you don't actually need streaming (i.e. you need the whole data at a time) consider using File.ReadAllText which will do all the work for you.

Read also:

• Cleaning up unmanaged resources

• https://stackoverflow.com/questions/538060/proper-use-of-the-idisposable-interface

> I'm curious to know if it can be written more succinctly.

You can use File.ReadAllText or File.ReadAllTextAsync methods instead.

They create and dispose StreamReader under the hood.