您如何从MemoryStream获取字符串？

Question

如果给我一个MemoryStream我知道已填充的String，我该如何String退出？

Answer 1

此示例说明如何向MemoryStream读取和写入字符串。

Imports System.IO

Module Module1

  Sub Main()

    ' We don't need to dispose any of the MemoryStream 

    ' because it is a managed object. However, just for 

    ' good practice, we'll close the MemoryStream.

    Using ms As New MemoryStream

      Dim sw As New StreamWriter(ms)

      sw.WriteLine("Hello World")

      ' The string is currently stored in the 

      ' StreamWriters buffer. Flushing the stream will 

      ' force the string into the MemoryStream.

      sw.Flush()

      ' If we dispose the StreamWriter now, it will close 

      ' the BaseStream (which is our MemoryStream) which 

      ' will prevent us from reading from our MemoryStream

      'sw.Dispose()

      ' The StreamReader will read from the current 

      ' position of the MemoryStream which is currently 

      ' set at the end of the string we just wrote to it. 

      ' We need to set the position to 0 in order to read 

      ' from the beginning.

      ms.Position = 0

      Dim sr As New StreamReader(ms)

      Dim myStr = sr.ReadToEnd()

      Console.WriteLine(myStr)

      ' We can dispose our StreamWriter and StreamReader 

      ' now, though this isn't necessary (they don't hold 

      ' any resources open on their own).

      sw.Dispose()

      sr.Dispose()

    End Using

    Console.WriteLine("Press any key to continue.")

    Console.ReadKey()

  End Sub

End Module

Answer 2

您也可以使用

Encoding.ASCII.GetString(ms.ToArray());

我认为这样做效率不高，但我不能对此宣誓。它还允许您选择其他编码，而使用StreamReader则必须将其指定为参数。

Answer 3

使用StreamReader将MemoryStream转换为字符串。

<Extension()> _

Public Function ReadAll(ByVal memStream As MemoryStream) As String

    ' Reset the stream otherwise you will just get an empty string.

    ' Remember the position so we can restore it later.

    Dim pos = memStream.Position

    memStream.Position = 0

    Dim reader As New StreamReader(memStream)

    Dim str = reader.ReadToEnd()

    ' Reset the position so that subsequent writes are correct.

    memStream.Position = pos

    Return str

End Function