File class static methods in C Sharp (C#) - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the File.Exists method in C#?

The File.Exists method checks if a file exists at a specified path and returns true if it does, otherwise false.

beginner

How does File.ReadAllText work?

It reads all the text from a file at a given path and returns it as a single string.

beginner

What does File.WriteAllText do?

It creates a new file or overwrites an existing file with the specified text content.

beginner

Explain the use of File.Delete.

The File.Delete method removes a file from the file system at the specified path if it exists.

intermediate

What does File.Copy do and what important parameter does it have?

It copies a file from a source path to a destination path. It has an optional parameter to specify whether to overwrite the destination file if it already exists.

Which File method reads all lines from a file into a string array?

A File.ReadAllText

B File.ReadAllLines

C File.WriteAllText

D File.Exists

File.ReadAllLines reads each line of a file into an array of strings.

What does File.Exists return if the file does not exist?

A throws an exception

B true

C null

D false

File.Exists returns false if the file is not found.

Which method would you use to overwrite a file with new text content?

A File.WriteAllText

B File.Delete

C File.Copy

D File.ReadAllText

File.WriteAllText creates or overwrites a file with the given text.

What happens if you call File.Delete on a file that does not exist?

A Does nothing

B Throws an exception

C Creates a new file

D Returns false

File.Delete does nothing if the file is not found; it does not throw an error.

Which parameter in File.Copy controls overwriting the destination file?

A append (bool)

B bufferSize (int)

C overwrite (bool)

D recursive (bool)

The overwrite boolean parameter specifies if the destination file should be overwritten.

Describe how you would check if a file exists and then read its entire content using File class static methods.

Think about checking first to avoid errors.

Explain the difference between File.WriteAllText and File.AppendAllText.

Consider what happens to existing file content.