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 |
| Rename or move a file. | File.Move |
| Delete a file. | File.Delete |
| Copy a file. | File.Copy |
| 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
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