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如何将原始图像数据获取到 VB.NET 中的字符串，类似于以下内容：

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我目前的代码是：

Dim FileName As String = "Image.jpg"
Dim ImageData() As Byte = File.ReadAllBytes(ProfileImagePath)
Dim NewImageData As String = Convert.ToBase64String(ImageData)

这将返回 Base64 代码，但我正在尝试获取上面示例中的实际原始数据，以便我可以发布到也以这种方式发布的分段上传表单。

我上传的完整代码是：

Dim boundary As String = "-----------------------------" & DateTime.Now.Ticks.ToString("x")
        Dim req As HttpWebRequest = DirectCast(WebRequest.Create("http://www.mysite.com/upload.php"), HttpWebRequest)
        req.Method = "POST"
        req.ContentType = "multipart/form-data; boundary=" & "---------------------------" & DateTime.Now.Ticks.ToString("x")
        req.KeepAlive = False
        Dim builder As New StringBuilder()
        builder.Append(boundary & vbCrLf & "Content-Disposition: form-data; name=""variable1""" & vbCrLf & vbCrLf & "1" & vbCrLf)
        builder.Append(boundary & vbCrLf & "Content-Disposition: form-data; name=""file""; filename=""" & FileName & """" & vbCrLf)
        builder.Append("Content-Type: application/octet-stream")
        builder.Append(vbCrLf & vbCrLf)
        ' Add Photo Here
        If UpdateImage = True Then
            ' Load Image
            Dim ImageData() As Byte = File.ReadAllBytes(ProfileImagePath)
            Dim NewImageData As String = Convert.ToBase64String(ImageData)
            ' Add Image To Header
            builder.Append(NewImageData)
            builder.Append(vbCrLf)
        Else
            builder.Append(vbCrLf)
        End If
        builder.Append(boundary & vbCrLf & "Content-Disposition: form-data; name=""save""" & vbCrLf & vbCrLf & "save")
        ' Footer Bytes
        Dim close As Byte() = Encoding.UTF8.GetBytes("--")
        Dim postHeader As String = builder.ToString()
        Dim postHeaderBytes As Byte() = Encoding.UTF8.GetBytes(postHeader)
        Dim boundaryBytes As Byte() = Encoding.ASCII.GetBytes(vbCrLf & boundary & "--" & vbCrLf)
        Dim length As Long = postHeaderBytes.Length + boundaryBytes.Length
        req.ContentLength = length
        Dim requestStream As Stream = req.GetRequestStream()
        Dim fulllength As Integer = postHeaderBytes.Length + boundaryBytes.Length
        ' Write out our post header
        requestStream.Write(postHeaderBytes, 0, postHeaderBytes.Length)
        ' Write out the trailing boundary
        requestStream.Write(boundaryBytes, 0, boundaryBytes.Length)
        Dim responce As WebResponse
        responce = req.GetResponse()
        requestStream.Close()
        Dim s As Stream = responce.GetResponseStream()
        Dim sr As New StreamReader(s)
        Dim Content As String = sr.ReadToEnd()
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1 回答 1

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这将返回 Base64 代码，但我正在尝试获取实际的原始数据，如上面的示例

“实际原始数据”不是文本数据，因此您根本不应该将其放在字符串中；至少不是没有像base64这样的东西。

If you want to post binary data, then either use base64 or post it as raw bytes, but not as text. Your data is not UTF-8-encoded text, so don't try to use it as if it were.

(I can't remember the details of multi-part form data; if you can specify a part length before the part itself, then you should be fine to include the binary data directly. If it's always just delimited by some separator, then you may want to use base64 instead.)

于 2012-12-19T18:44:34.167 回答