FileInfo.Exists Property
Definition
Important
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Gets a value indicating whether a file exists.
public:
virtual property bool Exists { bool get(); };public override bool Exists { get; }member this.Exists : boolPublic Overrides ReadOnly Property Exists As BooleanProperty Value
true if the file exists; false if the file does not exist or if the file is a directory.
Examples
The following code example uses the Exists property ensure a file exists before opening it. You can use this technique to throw a custom exception when the file is not found.
array<Byte>^ Openfile(String^ fileName)
{
// Check the fileName argument.
if (fileName == nullptr || fileName->Length == 0)
{
throw gcnew ArgumentNullException("fileName");
}
// Check to see if the file exists.
FileInfo^ fInfo = gcnew FileInfo(fileName);
// You can throw a personalized exception if
// the file does not exist.
if (!fInfo->Exists)
{
throw gcnew FileNotFoundException("The file was not found.",
fileName);
}
try
{
// Open the file.
FileStream^ fStream = gcnew FileStream(fileName, FileMode::Open);
// Create a buffer.
array<Byte>^ buffer = gcnew array<Byte>(fStream->Length);
// Read the file contents to the buffer.
fStream->Read(buffer, 0, (int)fStream->Length);
// return the buffer.
return buffer;
}
catch (IOException^ ex)
{
Console::WriteLine(ex->Message);
return nullptr;
}
}
public byte[] OpenDataFile(string FileName)
{
// Check the FileName argument.
if (FileName == null || FileName.Length == 0)
{
throw new ArgumentNullException("FileName");
}
// Check to see if the file exists.
FileInfo fInfo = new FileInfo(FileName);
// You can throw a personalized exception if
// the file does not exist.
if (!fInfo.Exists)
{
throw new FileNotFoundException("The file was not found.", FileName);
}
// Open the file.
FileStream fStream = new FileStream(FileName, FileMode.Open);
// Create a buffer.
byte [] buffer = new byte[fStream.Length];
// Read the file contents to the buffer.
fStream.Read(buffer, 0, (int)fStream.Length);
// return the buffer.
return buffer;
}
Function OpenDataFile(ByVal FileName As String) As Byte()
' Check the FileName argument.
If FileName Is Nothing OrElse FileName.Length = 0 Then
Throw New ArgumentNullException("FileName")
End If
' Check to see if the file exists.
Dim fInfo As New FileInfo(FileName)
' You can throw a personalized exception if
' the file does not exist.
If Not fInfo.Exists Then
Throw New FileNotFoundException("The file was not found.", FileName)
End If
' Open the file.
Dim fStream As New FileStream(FileName, FileMode.Open)
' Create a buffer.
Dim buffer(fStream.Length) As Byte
' Read the file contents to the buffer.
fStream.Read(buffer, 0, Fix(fStream.Length))
' return the buffer.
Return buffer
End Function
Remarks
When first called, FileInfo calls Refresh and caches information about the file. On subsequent calls, you must call Refresh to get the latest copy of the information.
The Exists property returns false if any error occurs while trying to determine if the specified file exists. This can occur in situations that raise exceptions such as passing a file name with invalid characters or too many characters, a failing or missing disk, or if the caller does not have permission to read the file.
