馬久里的部落格

這個需求是因為有個系統的資料需要大量拋傳到我們這方來，因此開始了我的第一支Web Service，

又是一個越級打怪的情況出現，之前連寫都沒寫過，爬文過後看起來不難，於是這個美麗的錯誤就開始了。

 

為何會說是美麗的錯誤，因為一開始想到既然是大量資料，那就用Datatable去做接收，結果出現error message

System.InvalidOperationException: 無法序列化 DataTable

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

據網友提供的消息，只要給Datable Name就不會出現此錯誤

 

爬文之後發現，Web service是不能傳送Datatalbe，最後SPEC就開始使用泛型List(of T) 去接收解決這個情況。

 

在我個人的腦袋中是一個袋子(list)，而袋子裡面放了幾本書(of T)(註一)，因此傳送或接收都是收到這個袋子，

然後我再把袋子裡面的書給取出，因此我的範例就是要這些袋子裡面的書的 -書名、價格、作者、數量等資訊。

 

*註一：of T可以是任何一種型別(所以才稱做泛型)

 

我的泛型是個傳送Class的架構，如下就是我的(of T)

Public Class Storybook
    Private _sbookname As String
    Private _iprice As Integer
    Private _sauthor As String
    Private _icount As Integer

    Public Property bookname() As String
        Get
            Return _sbookname
        End Get
        Set(ByVal value As String)
            _sbookname = value
        End Set
    End Property

    Public Property price() As Integer
        Get
            Return _iprice
        End Get
        Set(ByVal value As Integer)
            _iprice = value
        End Set
    End Property

    Public Property author() As String
        Get
            Return _sauthor
        End Get
        Set(ByVal value As String)
            _sauthor = value
        End Set
    End Property

    Public Property count() As Integer
        Get
            Return _icount
        End Get
        Set(ByVal value As Integer)
            _icount = value
        End Set
    End Property
End Class

 

我的WebService很單純如下

Public Class TransferData

    Inherits System.Web.Services.WebService

    Dim dt_bookdetail As New DataTable

     _
    Public Function ReceiveData(ByVal booklist As List(of SStorybook)) As String

        dt_bookdetail = getbookdetail(booklist)

        '這裡接回的資料就depend on what u wanna do(insert to ur Database or something else)
	Return dt_bookdetail.Rows.Count.ToString + " Records. Or U can Choice into to ur Database"

    End Function

    Private Function getbookdetail(ByVal booklist As List(Of Storybook)) As DataTable
        Dim newrow As DataRow = Nothing

        dt_bookdetail.Columns.Add("bookname")
        dt_bookdetail.Columns.Add("price")
        dt_bookdetail.Columns.Add("author")
        dt_bookdetail.Columns.Add("count")

        For Each Data As Storybook In booklist
            newrow = dt_bookdetail.NewRow
            newrow(0) = Data.bookname
            newrow(1) = Data.price
            newrow(2) = Data.author
            newrow(3) = Data.count

            dt_bookdetail.Rows.Add(newrow)
        Next

        Return dt_bookdetail

    End Function
End Class

 

如此就完成了，為了確認我的web service能正常的交給對方使用，我開了一個新的page模擬

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

        '模擬傳送大量資料

        Dim storelist As New Storybook

        Dim ls As New List(Of Storybook)

        For i As Integer = 0 To 10

            storelist.author = "unknow"
            storelist.bookname = "睡美人"
            storelist.count = 100
            storelist.price = 10

            ls.Add(storelist)

        Next

        Dim senddata As New TransferData

        Response.Write(senddata.ReceiveData(ls))


    End Sub

 

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