UnmanagedMemoryStream.WriteByte(Byte) Metode

Definisi

Ruang nama:

System.IO

Rakitan:

System.Runtime.dll

Sumber:

UnmanagedMemoryStream.cs

Menulis byte ke posisi saat ini di aliran file.

public:
 override void WriteByte(System::Byte value);

public override void WriteByte (byte value);

override this.WriteByte : byte -> unit

Public Overrides Sub WriteByte (value As Byte)

Parameter

value

Byte

Nilai byte yang ditulis ke aliran.

Pengecualian

ObjectDisposedException

Aliran ditutup.

NotSupportedException

Memori yang mendasar tidak mendukung penulisan.

-atau-

Upaya dilakukan untuk menulis ke aliran dan CanWrite properti adalah false.

-atau-

Posisi saat ini berada di akhir kapasitas aliran.

IOException

Yang disediakan value menyebabkan aliran melebihi kapasitas maksimumnya.

Contoh

Contoh kode berikut menunjukkan cara membaca dari dan menulis ke memori yang tidak dikelola menggunakan UnmanagedMemoryStream kelas . Blok memori yang tidak dikelola dialokasikan dan dibatalkan alokasinya Marshal menggunakan kelas . Dalam contoh ini, UnmanagedMemoryStream objek diteruskan ke metode yang memeriksa CanWrite properti sebelum mencoba menulis data ke aliran.

// Note: You must compile this sample using the unsafe flag.
// From the command line, type the following: csc sample.cs /unsafe
using System;
using System.IO;
using System.Runtime.InteropServices;
using System.Text;

unsafe class Program
{
    static void Main()
    {
        // Create some data to write.
        byte[] text = UnicodeEncoding.Unicode.GetBytes("Data to write.");

        // Allocate a block of unmanaged memory.
        IntPtr memIntPtr = Marshal.AllocHGlobal(text.Length);

        // Get a byte pointer from the unmanaged memory block.
        byte* memBytePtr = (byte*)memIntPtr.ToPointer();

        UnmanagedMemoryStream writeStream =
            new UnmanagedMemoryStream(
            memBytePtr, text.Length, text.Length, FileAccess.Write);

        // Write the data.
        WriteToStream(writeStream, text);

        // Close the stream.
        writeStream.Close();

        // Create another UnmanagedMemoryStream for reading.
        UnmanagedMemoryStream readStream =
            new UnmanagedMemoryStream(memBytePtr, text.Length);

        // Display the contents of the stream to the console.
        PrintStream(readStream);

        // Close the reading stream.
        readStream.Close();

        // Free up the unmanaged memory.
        Marshal.FreeHGlobal(memIntPtr);
    }

    public static void WriteToStream(UnmanagedMemoryStream writeStream, byte[] text)
    {
        // Verify that the stream is writable:
        // By default, UnmanagedMemoryStream objects do not have write access,
        // write access must be set explicitly.
        if (writeStream.CanWrite)
        {
            // Write the data, byte by byte
            for (int i = 0; i < writeStream.Length; i++)
            {
                writeStream.WriteByte(text[i]);
            }
        }
    }

    public static void PrintStream(UnmanagedMemoryStream readStream)
    {
        byte[] text = new byte[readStream.Length];
        // Verify that the stream is writable:
        // By default, UnmanagedMemoryStream objects do not have write access,
        // write access must be set explicitly.
        if (readStream.CanRead)
        {
            // Write the data, byte by byte
            for (int i = 0; i < readStream.Length; i++)
            {
                text[i] = (byte)readStream.ReadByte();
            }
        }

        Console.WriteLine(UnicodeEncoding.Unicode.GetString(text));
    }
}