我需要幫助。我的程序有問題。這是我的業務邏輯層上的代碼。可爲空的對象必須有一個值。 VB.NET
Function Load_ItemDetails(ByVal ItemID As String) As Items
Dim objItemEnt As New tblitem
Dim objitem As New Items
Try
Using da = New DataAccess
objItemEnt = da.Load_ItemDetails(ItemID)
With objitem
.ItemCode = objItemEnt.ItemCode
.ItemName = objItemEnt.ItemName
.Description = objItemEnt.Description
.NameofType = objItemEnt.NameofType
.TypeofPricing = objItemEnt.TypeofPricing
.OnStock = objItemEnt.OnStock
.ItemPrice = objItemEnt.ItemPrice
.DateModified = objItemEnt.DateModified
End With
Return objitem
End Using
Catch ex As Exception
Throw
End Try
End Function
此代碼用於我的數據訪問層。
Public Function Load_ItemDetails(ByVal ItemCode As String)
Dim objitem As New tblitem
Try
Using entItem = New DAL.systemdbEntities1
Dim qryUsers = From p In entItem.tblitems
Where p.ItemCode = ItemCode
Select p
Dim luser As List(Of tblitem) = qryUsers.ToList
If luser.Count > 0 Then
Return luser.First
Else
Return objitem
End If
End Using
Catch ex As Exception
Throw
End Try
End Function`
對於我的表現層:
Private Sub Load_Item_Detail(ByVal ItemCode As String)
objItem = New Items
Using objLogic = New LogicalLayer
objItem = objLogic.Load_ItemDetails(ItemCode)
With objItem
Me.ItemCodetxt.Text = .ItemCode
Me.ItemNametxt.Text = .ItemName
Me.ItemDesctxt.Text = .Description
Me.ItemTypetxt.Text = .NameofType
Me.ItemPricetxt.Text = .TypeofPricing
Me.ItemOnstocktxt.Text = CStr(.OnStock)
Me.ItemPricetxt.Text = CStr(.ItemPrice)
Me.TextBox1.Text = CStr(.DateModified)
Me.ItemCodetxt.Tag = .ItemCode
End With
End Using
End Sub`
,我跑後,我得到這個錯誤Nullable object must have a value
幫助我。我卡住了。我不知道該做什麼。我是新的n層架構。
它與架構無關。而且你的代碼被削減並不能提供足夠的數據來幫助你解決問題。 – MarcinJuraszek
什麼對象可以爲空? – OneFineDay
這個'.OnStock = objItemEnt.OnStock' – Gcode