The Exists method should not be used for path validation, this method merely checks if the file specified in path exists. Passing an invalid path to Existsl returns false.

Be aware that another process can potentially do something with the file in between the time you call the Exists method and perform another operation on the file, such as Delete. A recommended programming practice is to wrap the Exists method, and the operations you take on the file, in a try...catch block as shown in the example. This helps to narrow the scope for potential conflicts. The Exists method can only help to ensure that the file will be available, it cannot guarantee it.

The path parameter is permitted to specify relative or absolute path information. Relative path information is interpreted as relative to the current working directory. To obtain the current working directory, see GetCurrentDirectory.

If path describes a directory, this method returns false. Trailing spaces are removed from the path parameter before determining if the file exists.

The following example uses the Exists method to help ensure that a file is not overwritten.

Imports System
Imports System.IO


Public Class Test
    Public Shared Sub Main()
        Dim sourceFile As String = "c:\tests\Test.txt"
        Dim newFile As String = "c:\tests\Test2.txt"

        If File.Exists(sourceFile) Then
            File.Copy(sourceFile, newFile)
        Else
            Console.WriteLine("Source file does not exist.")
        End If
    End Sub
End Class

using System;
using System.IO;

class Test
{
    public static void Main()
    {
        string sourceFile = @"c:\tests\Test.txt";
        string newFile = @"c:\tests\Test2.txt";
        if (File.Exists(sourceFile))
        {

            File.Copy(sourceFile, newFile);

        }
        else
        {
            Console.WriteLine("Source file does not exist.");

        }
    }
}

• FileIOPermission 

  for reading from the specified file. Associated enumeration: FileIOPermissionAccess..::.Read

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

.NET Framework

.NET Compact Framework

XNA Framework

Reference

Other Resources