UnmanagedMemoryStream.WriteByte(Byte) 方法

定義

命名空間:

System.IO

組件:

netstandard.dll, System.Runtime.dll

來源:

UnmanagedMemoryStream.cs

會將一個位元組寫入檔案串流的當前位置。

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)

參數

value

Byte

一個寫入串流的位元組值。

例外狀況

ObjectDisposedException

溪流已經關閉。

NotSupportedException

底層記憶體不支援寫入。

-或-

嘗試寫入串流，屬性 CanWrite 為 false。

-或-

目前位置位於溪流容量的盡頭。

IOException

供應 value 導致水流超過最大容量。

範例

以下程式碼範例示範如何使用類別讀取與寫入未管理記憶體 UnmanagedMemoryStream 。 使用類別 Marshal 分配與取消管理的記憶體區塊。 在此範例中，物件 UnmanagedMemoryStream 會傳送給一個方法，該方法在嘗試將資料寫入串流前檢查該 CanWrite 屬性。

// 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));
    }
}