C# FileInfo
last modified May 18, 2025
In this article, we explore how FileInfo facilitates file
management in C#.
Understanding FileInfo
The FileInfo class provides a range of properties and instance
methods for handling files, including creation, copying, deletion, moving, and
opening operations. It also supports the initialization of
FileStream objects, allowing efficient file access and
manipulation.
.NET also includes the File class, which serves a similar purpose
but differs in functionality. While FileInfo represents a specific
file instance and enables detailed file operations, File is a
static utility class that provides convenient methods for working with files
without requiring an object instance.
Using FileInfo is beneficial when you need to retrieve file
metadata, perform multiple operations on a file, or optimize performance by
reducing redundant security checks. On the other hand, File is
ideal for simple file operations that do not require persistent file objects.
sky borrow war ocean cup cloud water read book look
In several examples, we use this text file.
C# FileInfo simple example
We have a simple example with FileInfo.
var fi = new FileInfo("words.txt");
Console.WriteLine(fi.Name);
Console.WriteLine(fi.FullName);
bool ro = fi.IsReadOnly;
if (ro)
{
Console.WriteLine("readonly file");
}
else
{
Console.WriteLine("not a readonly file");
}
We create a FileInfo object, passing a text file to its
constructor. Then we print its three properties.
Console.WriteLine(fi.Name); Console.WriteLine(fi.FullName);
We print its name and fullname.
bool ro = fi.IsReadOnly;
if (ro)
{
Console.WriteLine("readonly file");
}
else
{
Console.WriteLine("not a readonly file");
}
We determine whether the file is readonly.
$ dotnet run words.txt /home/jano/Documents/prog/csharp/fileinfo/First/words.txt not a readonly file
C# FileInfo create text file
The CreateText method creates a StreamWriter that
writes a new text file.
var fi = new FileInfo("colours.txt");
using StreamWriter sw = fi.CreateText();
sw.WriteLine("red");
sw.WriteLine("yellow");
sw.WriteLine("white");
sw.WriteLine("brown");
We create a new text file colours.txt. We write four lines into the
file.
using StreamWriter sw = fi.CreateText();
The StreamWriter class implements the IDisposable
interface; therefore, we use the using statement to close the
resources when we are done.
C# FileInfo read file
The OpenText creates a StreamReader with UTF8 encoding
that reads from an existing text file.
var fi = new FileInfo("words.txt");
using StreamReader sr = fi.OpenText();
string? s = string.Empty;
while ((s = sr.ReadLine()) != null)
{
Console.WriteLine(s);
}
In the example, we read a file line by line.
$ dotnet run sky borrow war ocean cup cloud water read book look
C# FileInfo delete file
The Delete method deletes a file.
var fi = new FileInfo("/etc/hostname");
try
{
fi.Delete();
} catch (UnauthorizedAccessException e)
{
Console.WriteLine("failed to delete file");
Console.WriteLine(e.Message);
}
In the example, we try to delete a system file. Since we do not have enough permissions, an exception is thrown.
$ dotnet run failed to delete file Access to the path '/etc/hostname' is denied.
C# FileInfo copy file
The CopyTo copies an existing file to a new file, disallowing the
overwriting of an existing file.
var fi = new FileInfo("words.txt");
fi.CopyTo("words2.txt");
The example creates a copy of the words.txt file.
C# FileInfo Directory
The Directory gets an instance of the parent directory.
var fi = new FileInfo("/etc/hostname");
var di = fi.Directory;
Console.WriteLine(di?.FullName);
Console.WriteLine(di?.LastAccessTime);
Console.WriteLine(di?.Root);
The example prints the file's parent directory fullname, last access time and root directory.
$ dotnet run /etc 6/30/2022 11:46:07 AM /
C# FileInfo rename file
You can rename a file by using the MoveTo method of
FileInfo. This method moves the file to a new path, which can
include a new name.
var fi = new FileInfo("words.txt");
if (fi.Exists)
{
fi.MoveTo("words_renamed.txt");
Console.WriteLine("File renamed to words_renamed.txt");
}
else
{
Console.WriteLine("File does not exist.");
}
This example checks if words.txt exists and renames it to
words_renamed.txt.
$ dotnet run File renamed to words_renamed.txt
C# FileInfo check if file exists
Before performing file operations, it is good practice to check if the file
exists using the Exists property.
var fi = new FileInfo("words.txt");
if (fi.Exists)
{
Console.WriteLine("File exists.");
}
else
{
Console.WriteLine("File does not exist.");
}
This example prints a message depending on whether words.txt exists.
$ dotnet run File exists.
C# FileInfo append text to file
The AppendText method opens an existing file for appending text. If
the file does not exist, it creates a new one.
var fi = new FileInfo("words.txt");
using (StreamWriter sw = fi.AppendText())
{
sw.WriteLine("newword");
}
Console.WriteLine("Text appended to file.");
This example appends the word newword to words.txt.
$ dotnet run Text appended to file.
Source
FileInfo class - language reference
In this article we have used FileInfo to work with files.
Author
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