Stream.CanRead Stream.CanRead Stream.CanRead Stream.CanRead Property

定義

在衍生類別中覆寫時,取得指示目前的資料流是否支援讀取的數值。When overridden in a derived class, gets a value indicating whether the current stream supports reading.

public:
 abstract property bool CanRead { bool get(); };
public abstract bool CanRead { get; }
member this.CanRead : bool
Public MustOverride ReadOnly Property CanRead As Boolean

屬性值

如果資料流支援讀取,則為 true;否則為 falsetrue if the stream supports reading; otherwise, false.

範例

以下是使用的範例CanRead屬性。The following is an example of using the CanRead property.

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
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

備註

如果類別衍生自Stream不支援讀取,呼叫ReadReadByte,以及BeginRead方法會擲回NotSupportedExceptionIf a class derived from Stream does not support reading, calls to the Read, ReadByte, and BeginRead methods throw a NotSupportedException.

如果資料流已關閉,則這個屬性會傳回falseIf the stream is closed, this property returns false.

適用於

另請參閱