我有以下内容:
公共接口INorthwindSvc
<OperationContract()>
<WebGet(UriTemplate:="EmployeePictureBytes?id={EmpId}")>
Function GetEmployeePictureBytesById(ByVal EmpId As String) As Byte()
结束界面
我按如下方式实现了(使用EF 4.0)方法:
Public Function GetEmployeePictureBytesById(ByVal EmpId As String) As Byte() Implements INorthwindSvc.GetEmployeePictureBytesById
Dim ctxt As New NorthwindEntities
Dim q = From c In ctxt.Employees
Where c.EmployeeID = EmpId
Select c.Photo
Return q.FirstOrDefault
End Function
当我从浏览器访问操作时,我能够接收字节。如果我尝试使用Win Client访问相同的内容(如内联所示发生错误):
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim o As New WebClient
Dim b() As Byte = o.DownloadData(New Uri("http://localhost:8732/WcfWebHttpSvcLib/rest/EmployeePictureBytes?id=2"))
Dim ms As New MemoryStream()
ms.Write(b, 0, b.Length)
Dim original As New System.Drawing.Bitmap(ms) 'error: parameter is not valid
End Sub
我也尝试使用Image.FromStream。但是,仍然没有运气。
有人可以帮我吗?
感谢
答案 0 :(得分:0)
写入后你没有倒回内存流,所以尝试读取它会失败那就是说,即使这是不必要的,你可以写一下:
im ms As New MemoryStream(b)
' now call FromStream