ASP.NET Web服务返回400

Question

If I de-serialize the data and an error occurs later in the update process (for example: the change fails to meet a database constraint). I'd like to report something useful to the end user here, but it looks like .NET is swallowing the error. Any idea why?

<WebInvoke(method:="POST", uriTemplate:="changes", bodyStyle:=WebMessageBodyStyle.Bare)>
Public Function PostChanges(body As Stream) As String
    Try
        ' This returns 500 Server Error (with wrapped exception)
        'Throw New Exception("TEST")

        Dim data As String = ""
        Using reader As New StreamReader(body)
            data = reader.ReadToEnd()
        End Using

        ' This returns 400 Bad Request
        'Throw New Exception("TEST")

        ' Code handling data removed (no error if exceptions are removed)
    Catch ex As Exception
        Throw New WebFaultException(Of DisplayError)(New DisplayError(ex.Message, ex.StackTrace), Net.HttpStatusCode.InternalServerError)
    End Try

Answer 1

Apparently, StreamReader disposes of its underlying Stream object which causes problem if your code has the temerity to break normal flow by raising an exception.

So, now I'm using OperationContext.Current.RequestContext.RequestMessage.ToString, which has its own problems but at least I'm not choosing between messed up error logging or a resource leak.