FileStream.CanRead Propriedade
Definição
Obtém um valor que indica se o fluxo atual dá suporte a leitura.Gets a value that indicates whether the current stream supports reading.
public:
virtual property bool CanRead { bool get(); };
public override bool CanRead { get; }
member this.CanRead : bool
Public Overrides ReadOnly Property CanRead As Boolean
Valor da propriedade
true se o fluxo dá suporte à leitura; false se o fluxo está fechado ou foi aberto com acesso somente gravação.true if the stream supports reading; false if the stream is closed or was opened with write-only access.
Exemplos
O exemplo a seguir demonstra um uso da CanRead propriedade.The following example demonstrates a use of the CanRead property. A saída desse código é "MyFile.txt não é gravável".The output of this code is "MyFile.txt is not writable." Para obter a mensagem de saída "MyFile.txt pode ser gravado e lido de.", altere o FileAccess parâmetro para ReadWrite no FileStream Construtor.To get the output message "MyFile.txt can be both written to and read from.", change the FileAccess parameter to ReadWrite in the FileStream constructor.
using namespace System;
using namespace System::IO;
int main( void )
{
FileStream^ fs = gcnew FileStream( "MyFile.txt",FileMode::OpenOrCreate,FileAccess::Read );
if ( fs->CanRead && fs->CanWrite )
{
Console::WriteLine( "MyFile.txt can be both written to and read from." );
}
else
{
Console::WriteLine( "MyFile.txt is not writable" );
}
return 0;
}
using System;
using System.IO;
class TestRW
{
public static void Main(String[] args)
{
FileStream fs = new FileStream("MyFile.txt", FileMode.OpenOrCreate, FileAccess.Read);
if (fs.CanRead && fs.CanWrite)
{
Console.WriteLine("MyFile.txt can be both written to and read from.");
}
else if (fs.CanRead)
{
Console.WriteLine("MyFile.txt is not writable.");
}
}
}
Imports System.IO
Class TestRW
Public Shared Sub Main()
Dim fs As New FileStream("MyFile.txt", FileMode.OpenOrCreate, FileAccess.Read)
If fs.CanRead And fs.CanWrite Then
Console.WriteLine("MyFile.txt can be both written to and read from.")
Else
If fs.CanRead Then
Console.WriteLine("MyFile.txt is not writable.")
End If
End If
End Sub
End Class
Comentários
Se uma classe derivada de não Stream oferecer suporte à leitura, as chamadas para os Read ReadByte métodos, e BeginRead lançarão um NotSupportedException .If a class derived from Stream does not support reading, calls to the Read, ReadByte, and BeginRead methods throw a NotSupportedException.
Se o fluxo for fechado, essa propriedade retornará false .If the stream is closed, this property returns false.