If I am given a MemoryStream
that I know has been populated with a String
, how do I get a String
back out?
To convert an InputStream Object int to a String using this method. Instantiate the Scanner class by passing your InputStream object as parameter. Read each line from this Scanner using the nextLine() method and append it to a StringBuffer object. Finally convert the StringBuffer to String using the toString() method.
To get the entire buffer, use the GetBuffer method. This method returns a copy of the contents of the MemoryStream as a byte array. If the current instance was constructed on a provided byte array, a copy of the section of the array to which this instance has access is returned.
You can re-use the MemoryStream by Setting the Position to 0 and the Length to 0. By setting the length to 0 you do not clear the existing buffer, it only resets the internal counters.
This sample shows how to read and write a string to a MemoryStream.
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
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