Is file empty check

How do I check if a file is empty in C#?

I need something like:

if (file is empty)
{
    // do stuff
}

else
{
    // do other stuff
}

Use FileInfo.Length:

if( new FileInfo( "file" ).Length == 0 )
{
  // empty
}

Check the Exists property to find out, if the file exists at all.

FileInfo.Length would not work in all cases, especially for text files. If you have a text file that used to have some content and now is cleared, the length may still not be 0 as the byte order mark may still retain.

You can reproduce the problem by creating a text file, adding some Unicode text to it, saving it, and then clearing the text and saving the file again.

Now FileInfo.Length will show a size that is not zero.

A solution for this is to check for Length < 6, based on the max size possible for byte order mark. If your file can contain single byte or a few bytes, then do the read on the file if Length < 6 and check for read size == 0.

public static bool IsTextFileEmpty(string fileName)
{
    var info = new FileInfo(fileName);
    if (info.Length == 0)
        return true;

    // only if your use case can involve files with 1 or a few bytes of content.
    if (info.Length < 6)
    {
        var content = File.ReadAllText(fileName);   
        return content.Length == 0;
    }
    return false;
}

The problem here is that the file system is volatile. Consider:

if (new FileInfo(name).Length > 0)
{  //another process or the user changes or even deletes the file right here

    // More code that assumes and existing, empty file
}
else
{


}

This can and does happen. Generally, the way you need to handle file-io scenarios is to re-think the process to use exceptions blocks, and then put your development time into writing good exception handlers.

if (!File.Exists(FILE_NAME))
{
    Console.WriteLine("{0} does not exist.", FILE_NAME);
    return;
}

if (new FileInfo(FILE_NAME).Length == 0)  
{  
    Console.WriteLine("{0} is empty", FILE_NAME);
    return;
} 

I've found that checking the FileInfo.Length field doesn't always work for certain files. For instance, and empty .pkgdef file has a length of 3. Therefore, I had to actually read all the contents of the file and return whether that was equal to empty string.

This is how I solved the problem. It will check if the file exists first then check the length. I'd consider a non-existent file to be effectively empty.

var info = new FileInfo(filename);
if ((!info.Exists) || info.Length == 0)
{
	// file is empty or non-existant	
}

In addition to answer of @tanascius, you can use

try
{
    if (new FileInfo("your.file").Length == 0)
    {
        //Write into file, i guess    
    }
} 
catch (FileNotFoundException e) 
{
    //Do anything with exception
}

And it will do it only if file exists, in catch statement you could create file, and run code agin.

What if file contains space? FileInfo("file").Length is equal to 2.
But I think that file is also empty (does not have any content except spaces (or line breaks)).

I used something like this, but does anybody have better idea?
May help to someone.

string file = "file.csv";
var fi = new FileInfo(file);
if (fi.Length == 0 || 
	(fi.Length < 100000 
     && !File.ReadAllLines(file)
        .Where(l => !String.IsNullOrEmpty(l.Trim())).Any()))
{
	//empty file
}

You can use this function if your file exists and is always copied to your debug/release directory.

/// <summary>
/// Include a '/' before your filename, and ensure you include the file extension, ex. "/myFile.txt"
/// </summary>
/// <param name="filename"></param>
/// <returns>True if it is empty, false if it is not empty</returns>
private Boolean CheckIfFileIsEmpty(string filename)
{
    var fileToTest = new FileInfo(Environment.CurrentDirectory + filename);
    return fileToTest.Length == 0;
}