Owin:
    <HttpPost>
    Function UploadFileOwin() As IHttpActionResult ‘Owin方式文件上传
        If Request.Content.IsMimeMultipartContent("form-data") Then
            Dim ParentPath As String = System.Environment.CurrentDirectory & "/UploadFiles/"
            If Not Directory.Exists(ParentPath) Then
                Directory.CreateDirectory(ParentPath)
            End If
            Dim Provider = Request.Content.ReadAsMultipartAsync.Result
            If Provider.Contents.Count > 0 Then
                For Each c In Provider.Contents
                    If c.Headers.ContentDisposition.FileName <> "" Then
                        Dim filePath As String = String.Concat(ParentPath, c.Headers.ContentDisposition.FileName.Replace("""", ""))
                        Using fs As FileStream = New FileStream(filePath, FileMode.OpenOrCreate)
                            Using ioStream = c.ReadAsStreamAsync.Result
                                Dim buff As Byte() = New Byte(ioStream.Length) {}
                                Dim co = ioStream.Read(buff, 0, ioStream.Length)
                                Using memStream = New MemoryStream(buff)
                                    memStream.WriteTo(fs)
                                    Return Ok("上传成功")
                                End Using
                            End Using
                        End Using
                    End If
                Next
            End If
        End If
        Return Ok("上传失败")
    End Function

mvc:
　　

    <HttpPost>
    Function UploadFileMVC() As String ‘MVC方式上传文件
        Dim result = String.Empty
        Dim uploadPath As String = HttpContext.Current.Server.MapPath("~/upload/")
        ‘Dim uploadPath As String = System.Web.Hosting.HostingEnvironment.MapPath("~/upload/")
        Dim request As HttpRequest = HttpContext.Current.Request
        Dim fileCollection As HttpFileCollection = request.Files
        If fileCollection.Count > 0 Then
            Dim httpPostedFile As HttpPostedFile = fileCollection(0)
            Dim fileExtension As String = Path.GetExtension(httpPostedFile.FileName)
            Dim fileName As String = Guid.NewGuid().ToString() + fileExtension
            Dim filePath As String = uploadPath + httpPostedFile.FileName
            If Not Directory.Exists(uploadPath) Then
                Directory.CreateDirectory(uploadPath)
            End If
            While File.Exists(filePath)
                fileName = Guid.NewGuid().ToString() + fileExtension
                filePath = uploadPath + fileName
            End While
            httpPostedFile.SaveAs(filePath)
            Return "上传成功"
        End If
        Return "文件上传失败"
    End Function