MemoryStream 類別

定義

public ref class MemoryStream : System::IO::Stream

public class MemoryStream : System.IO.Stream

[System.Serializable]
public class MemoryStream : System.IO.Stream

[System.Serializable]
[System.Runtime.InteropServices.ComVisible(true)]
public class MemoryStream : System.IO.Stream

type MemoryStream = class
    inherit Stream

[<System.Serializable>]
type MemoryStream = class
    inherit Stream

[<System.Serializable>]
[<System.Runtime.InteropServices.ComVisible(true)>]
type MemoryStream = class
    inherit Stream

Public Class MemoryStream
Inherits Stream

繼承

Object

Stream

MemoryStream

繼承

Object

MarshalByRefObject

Stream

MemoryStream

屬性

SerializableAttribute ComVisibleAttribute

範例

以下程式碼範例展示了如何利用記憶體作為後備儲存來讀寫資料。

using System;
using System.IO;
using System.Text;

class MemStream
{
    static void Main()
    {
        int count;
        byte[] byteArray;
        char[] charArray;
        UnicodeEncoding uniEncoding = new UnicodeEncoding();

        // Create the data to write to the stream.
        byte[] firstString = uniEncoding.GetBytes(
            "Invalid file path characters are: ");
        byte[] secondString = uniEncoding.GetBytes(
            Path.GetInvalidPathChars());

        using(MemoryStream memStream = new MemoryStream(100))
        {
            // Write the first string to the stream.
            memStream.Write(firstString, 0 , firstString.Length);

            // Write the second string to the stream, byte by byte.
            count = 0;
            while(count < secondString.Length)
            {
                memStream.WriteByte(secondString[count++]);
            }

            // Write the stream properties to the console.
            Console.WriteLine(
                "Capacity = {0}, Length = {1}, Position = {2}\n",
                memStream.Capacity.ToString(),
                memStream.Length.ToString(),
                memStream.Position.ToString());

            // Set the position to the beginning of the stream.
            memStream.Seek(0, SeekOrigin.Begin);

            // Read the first 20 bytes from the stream.
            byteArray = new byte[memStream.Length];
            count = memStream.Read(byteArray, 0, 20);

            // Read the remaining bytes, byte by byte.
            while(count < memStream.Length)
            {
                byteArray[count++] = (byte)memStream.ReadByte();
            }

            // Decode the byte array into a char array
            // and write it to the console.
            charArray = new char[uniEncoding.GetCharCount(
                byteArray, 0, count)];
            uniEncoding.GetDecoder().GetChars(
                byteArray, 0, count, charArray, 0);
            Console.WriteLine(charArray);
        }
    }
}

Imports System.IO
Imports System.Text

Module MemStream

    Sub Main()
    
        Dim count As Integer
        Dim byteArray As Byte()
        Dim charArray As Char()
        Dim uniEncoding As New UnicodeEncoding()

        ' Create the data to write to the stream.
        Dim firstString As Byte() = _
            uniEncoding.GetBytes("Invalid file path characters are: ")
        Dim secondString As Byte() = _
            uniEncoding.GetBytes(Path.GetInvalidPathChars())

        Dim memStream As New MemoryStream(100)
        Try
            ' Write the first string to the stream.
            memStream.Write(firstString, 0 , firstString.Length)

            ' Write the second string to the stream, byte by byte.
            count = 0
            While(count < secondString.Length)
                memStream.WriteByte(secondString(count))
                count += 1
            End While
            
            ' Write the stream properties to the console.
            Console.WriteLine( _
                "Capacity = {0}, Length = {1}, Position = {2}", _
                memStream.Capacity.ToString(), _
                memStream.Length.ToString(), _
                memStream.Position.ToString())

            ' Set the stream position to the beginning of the stream.
            memStream.Seek(0, SeekOrigin.Begin)

            ' Read the first 20 bytes from the stream.
            byteArray = _
                New Byte(CType(memStream.Length, Integer)){}
            count = memStream.Read(byteArray, 0, 20)

            ' Read the remaining Bytes, Byte by Byte.
            While(count < memStream.Length)
                byteArray(count) = _
                    Convert.ToByte(memStream.ReadByte())
                count += 1
            End While

            ' Decode the Byte array into a Char array 
            ' and write it to the console.
            charArray = _
                New Char(uniEncoding.GetCharCount( _
                byteArray, 0, count)){}
            uniEncoding.GetDecoder().GetChars( _
                byteArray, 0, count, charArray, 0)
            Console.WriteLine(charArray)
        Finally
            memStream.Close()
        End Try

    End Sub
End Module

備註

串流的當前位置是下一次讀寫操作可能發生的位置。 目前位置可以透過此 Seek 方法取得或設定。 當 建立新的實例時 MemoryStream ，當前位置會被設定為零。

使用無符號位元組陣列建立的記憶體串流，提供不可調整大小的資料串流。 使用位元組陣列時，你既不能附加也無法縮減串流，但你可能可以根據輸入建構子的參數修改現有內容。 空的記憶體串流可調整大小，且可寫入與讀取。

如果 MemoryStream 物件被加入 ResX 檔案或 .resources 檔案，執行時呼叫該 GetStream 方法以取得該物件。

如果一個 MemoryStream 物件被序列化成資源檔案，它實際上會被序列化為 UnmanagedMemoryStream。 這種行為提供了更好的效能，也讓它能直接取得資料的指標，而無需經過 Stream 其他方法。

另請參閱

• 檔案和數據流 I/O
• 如何：從檔案讀取文字
• 如何：將文字寫入檔案