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FileInfo.Length Property

Gets the size, in bytes, of the current file.

Namespace:  System.IO
Assembly:  mscorlib (in mscorlib.dll)

public long Length { get; }

Property Value

Type: System.Int64
The size of the current file in bytes.


Refresh cannot update the state of the file or directory.


The file does not exist.


The Length property is called for a directory.

The value of the Length property is pre-cached if the current instance of the FileInfo object was returned from any of the following DirectoryInfomethods:

To get the latest value, call the Refresh method.

The following example displays the size of the specified files.

// The following example displays the names and sizes 
// of the files in the specified directory. 
using System;
using System.IO;

public class FileLength
    public static void Main()
        // Make a reference to a directory.
        DirectoryInfo di = new DirectoryInfo("c:\\");
        // Get a reference to each file in that directory.
        FileInfo[] fiArr = di.GetFiles();
        // Display the names and sizes of the files.
        Console.WriteLine("The directory {0} contains the following files:", di.Name);
        foreach (FileInfo f in fiArr)
            Console.WriteLine("The size of {0} is {1} bytes.", f.Name, f.Length);
//This code produces output similar to the following;  
//results may vary based on the computer/file structure/etc.: 
//The directory c:\ contains the following files: 
//The size of MyComputer.log is 274 bytes. 
//The size of AUTOEXEC.BAT is 0 bytes. 
//The size of boot.ini is 211 bytes. 
//The size of CONFIG.SYS is 0 bytes. 
//The size of hiberfil.sys is 1072775168 bytes. 
//The size of IO.SYS is 0 bytes. 
//The size of MASK.txt is 2700 bytes. 
//The size of mfc80.dll is 1093632 bytes. 
//The size of mfc80u.dll is 1079808 bytes. 
//The size of MSDOS.SYS is 0 bytes. 
//The size of NTDETECT.COM is 47564 bytes. 
//The size of ntldr is 250032 bytes. 
//The size of pagefile.sys is 1610612736 bytes. 
//The size of UpdatePatch.log is 22778 bytes. 
//The size of UpdatePatch.txt is 30 bytes. 
//The size of wt3d.ini is 234 bytes.

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0, 2.0, 1.0

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8
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