Question

从WebResponse获取文件（在本例中为.PDF，但任何文件都可以）的最佳方法是什么，并将其放入MemoryStream？使用WebResponse中的.GetResponseStream（）获取Stream对象，但如果要将该Stream转换为特定类型的流，您会怎么做？

Answer 1

我在测试时发现SoloBold的answer存在严重问题。当使用它通过FtpWebRequest将文件读入MemoryStream时，它间歇性地无法将整个流读入内存。我将其跟踪到Peek()有时在前1460字节后返回-1，即使Read()成功（文件明显大于此）。

相反，我提出以下解决方案：

MemoryStream memStream;
using (Stream response = request.GetResponseStream()) {
    memStream = new MemoryStream();

    byte[] buffer = new byte[1024];
    int byteCount;
    do {
        byteCount = stream.Read(buffer, 0, buffer.Length);
        memStream.Write(buffer, 0, byteCount);
    } while (byteCount > 0);
}

// If you're going to be reading from the stream afterwords you're going to want to seek back to the beginning.
memStream.Seek(0, SeekOrigin.Begin);

// Use memStream as required

Answer 2

大约一年前从网上复制了这篇文章。

//---------- Start HttpResponse
if(objHttpWebResponse.StatusCode == HttpStatusCode.OK)
    {
        //Get response stream
        objResponseStream = objHttpWebResponse.GetResponseStream();

        //Load response stream into XMLReader
        objXMLReader = new XmlTextReader(objResponseStream);

        //Declare XMLDocument
        XmlDocument xmldoc = new XmlDocument();
        xmldoc.Load(objXMLReader);

        //Set XMLResponse object returned from XMLReader
        XMLResponse = xmldoc;

        //Close XMLReader
        objXMLReader.Close();
    }

    //Close HttpWebResponse
    objHttpWebResponse.Close();
}

Answer 3

我在http://social.msdn.microsoft.com/Forums/en-US/vbgeneral/thread/eeeefd81-8800-41b2-be63-71acdaddce0e/

找到了以下内容

    Dim request As WebRequest
    Dim response As WebResponse = Nothing
    Dim s As Stream = Nothing
    Dim fs As FileStream = Nothing
    Dim file As MemoryStream = Nothing

    Dim uri As New Uri(String.Format("http://forums.microsoft.com/forums/ShowPost.aspx?PostID=2992978&SiteID=1"))
    request = WebRequest.Create(uri)
    request.Timeout = 10000
    response = request.GetResponse
    s = response.GetResponseStream

    '2 - Receive file as memorystream
    Dim read(256) As Byte
    Dim count As Int32 = s.Read(read, 0, read.Length)
    File = New MemoryStream
    Do While (count > 0)
        File.Write(read, 0, count)
        count = s.Read(read, 0, read.Length)
    Loop
    File.Position = 0
    'Close responsestream
    s.Close()
    response.Close()

    '3 - Save file
    fs = New FileStream("c:\test.html", FileMode.CreateNew)
    count = file.Read(read, 0, read.Length)
    Do While (count > 0)
        fs.Write(read, 0, count)
        count = file.Read(read, 0, read.Length)
    Loop
    fs.Close()
    File.Close()

如何将WebResponse放入内存流？

3 个答案: