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FileInfo Class

Provides instance methods for the creation, copying, deletion, moving, and opening of files, and aids in the creation of FileStream objects.

For a list of all members of this type, see FileInfo Members.

System.Object
   System.MarshalByRefObject
      System.IO.FileSystemInfo
         System.IO.FileInfo

[Visual Basic]
<Serializable>
NotInheritable Public Class FileInfo
   Inherits FileSystemInfo
[C#]
[Serializable]
public sealed class FileInfo : FileSystemInfo
[C++]
[Serializable]
public __gc __sealed class FileInfo : public FileSystemInfo
[JScript]
public
   Serializable
class FileInfo extends FileSystemInfo

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Remarks

Use the FileInfo class for typical operations such as copying, moving, renaming, creating, opening, deleting, and appending to files.

Many of the FileInfo methods return other I/O types when you create or open files. You can use these other types to futher manipulate a file. For more information, see specific FileInfo members such as Open, OpenRead, OpenText, CreateText, or Create.

If you are going to reuse an object several times, consider using the instance method of FileInfo instead of the corresponding static methods of the File class, because a security check will not always be necessary.

By default, full read/write access to new files is granted to all users.

The following table describes the enumerations that are used to customize the behavior of various FileInfo methods.

Enumeration Description
FileAccess Specifies read and write access to a file.
FileShare Specifies the level of access permitted for a file that is already in use.
FileMode Specifies whether the contents of an existing file are preserved or overwritten, and whether requests to create an existing file cause an exception.
Note   In members that accept a path as an input string, that path must be well-formed or an exception is raised. For example, if a path is fully qualified but begins with a space, the path is not trimmed in methods of the class. Therefore, the path is malformed and an exception is raised. Similarly, a path or a combination of paths cannot be fully qualified twice. For example, "c:\temp c:\windows" also raises an exception in most cases. Ensure that your paths are well-formed when using methods that accept a path string.

In members that accept a path, the path can refer to a file or just a directory. The specified path can also refer to a relative path or a Universal Naming Convention (UNC) path for a server and share name. For example, all the following are acceptable paths:

  • "c:\\MyDir\\MyFile.txt" in C#, or "c:\MyDir\MyFile.txt" in Visual Basic.
  • "c:\\MyDir" in C#, or "c:\MyDir" in Visual Basic.
  • "MyDir\\MySubdir" in C#, or "MyDir\MySubDir" in Visual Basic.
  • "\\\\MyServer\\MyShare" in C#, or "\\MyServer\MyShare" in Visual Basic.

For an example of using this class, see the Example section below. The following table lists examples of other typical or related I/O tasks.

To do this... See the example in this topic...
Create a text file. Writing Text to a File
Write to a text file. Writing Text to a File
Read from a text file. Reading Text from a File
Append text to a file. Opening and Appending to a Log File

File.AppendText

FileInfo.AppendText

Rename or move a file. File.Move

FileInfo.MoveTo

Delete a file. File.Delete

FileInfo.Delete

Copy a file. File.Copy

FileInfo.CopyTo

Get the size of a file. FileInfo.Length
Get the attributes of a file. File.GetAttributes
Set the attributes of a file. File.SetAttributes
Determine if a file exists. File.Exists
Read from a binary file. Reading and Writing to a Newly Created Data File
Write to a binary file. Reading and Writing to a Newly Created Data File
Retrieve a file extension. Path.GetExtension
Retrieve the fully qualified path of a file. Path.GetFullPath
Retrieve the file name and extension from a path. Path.GetFileName
Change the extension of a file. Path.ChangeExtension

.NET Compact Framework Platform Note:  The .NET Compact Framework does not support getting or setting directory attributes.

Example

[Visual Basic, C#, C++] The following example demonstrates some of the main members of the FileInfo class.

[Visual Basic] 
Imports System
Imports System.IO

Public Class Test

    Public Shared Sub Main()
        Dim path As String = "c:\temp\MyTest.txt"
        Dim path2 As String = path + "temp"
        Dim fi As FileInfo = New FileInfo(path)

        If fi.Exists = False Then
            'Create a file to write to.
            Dim sw As StreamWriter = fi.CreateText()

            sw.WriteLine("Hello")
            sw.WriteLine("And")
            sw.WriteLine("Welcome")
            sw.Flush()
            sw.Close()
        End If

        Try
            'Open the file to read from.
            Dim sr As StreamReader = fi.OpenText()

            Do While sr.Peek() >= 0
                Console.WriteLine(sr.ReadLine())
            Loop
            sr.Close()
            Dim fi2 As FileInfo = New FileInfo(path2)

            'Ensure that the target does not exist.
            fi2.Delete()

            'Copy the file.
            fi.CopyTo(path2)
            Console.WriteLine("{0} was copied to {1}.", path, path2)

            'Delete the newly created file.
            fi2.Delete()
            Console.WriteLine("{0} was successfully deleted.", path2)

        Catch e As Exception
            Console.WriteLine("The process failed: {0}.", e.ToString())
        End Try
    End Sub
End Class

[C#] 
using System;
using System.IO;

class Test 
{
    
    public static void Main() 
    {
        string path = @"c:\temp\MyTest.txt";
        FileInfo fi1 = new FileInfo(path);

        if (!fi1.Exists) 
        {
            //Create a file to write to.
            using (StreamWriter sw = fi1.CreateText()) 
            {
                sw.WriteLine("Hello");
                sw.WriteLine("And");
                sw.WriteLine("Welcome");
            }    
        }

        //Open the file to read from.
        using (StreamReader sr = fi1.OpenText()) 
        {
            string s = "";
            while ((s = sr.ReadLine()) != null) 
            {
                Console.WriteLine(s);
            }
        }

        try 
        {
            string path2 = path + "temp";
            FileInfo fi2 = new FileInfo(path2);

            //Ensure that the target does not exist.
            fi2.Delete();

            //Copy the file.
            fi1.CopyTo(path2);
            Console.WriteLine("{0} was copied to {1}.", path, path2);

            //Delete the newly created file.
            fi2.Delete();
            Console.WriteLine("{0} was successfully deleted.", path2);

        } 
        catch (Exception e) 
        {
            Console.WriteLine("The process failed: {0}", e.ToString());
        }
    }
}

[C++] 
#using <mscorlib.dll>

using namespace System;
using namespace System::IO;

int main() {
    String* path = S"c:\\temp\\MyTest.txt";
    FileInfo* fi1 = new FileInfo(path);

    if (!fi1->Exists) {
        //Create a file to write to.
        StreamWriter* sw = fi1->CreateText();
        try {
            sw->WriteLine(S"Hello");
            sw->WriteLine(S"And");
            sw->WriteLine(S"Welcome");
        } __finally {
            if (sw) __try_cast<IDisposable*>(sw)->Dispose();
        }
    }

    //Open the file to read from.
    StreamReader* sr = fi1->OpenText();
    try {
        String* s = S"";
        while (s = sr->ReadLine()) {
            Console::WriteLine(s);
        }
    } __finally {
        if (sr) __try_cast<IDisposable*>(sr)->Dispose();
    }

    try {
        String* path2 = String::Concat(path, S"temp");
        FileInfo* fi2 = new FileInfo(path2);

        //Ensure that the target does not exist.
        fi2->Delete();

        //Copy the file.
        fi1->CopyTo(path2);
        Console::WriteLine(S"{0} was copied to {1}.", path, path2);

        //Delete the newly created file.
        fi2->Delete();
        Console::WriteLine(S"{0} was successfully deleted.", path2);
    } catch (Exception* e) {
        Console::WriteLine(S"The process failed: {0}", e);
    }
}

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Namespace: System.IO

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family, .NET Compact Framework

Assembly: Mscorlib (in Mscorlib.dll)

See Also

FileInfo Members | System.IO Namespace | Working with I/O | Reading Text from a File | Writing Text to a File | Basic File I/O | Reading and Writing to a Newly Created Data File

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