User759549661 posted
Hi,
I have a page where I’m trying to add a DetailsView (ID="License") control to conditionally display license information, if the user has a license. The control has ItemType="LabEle3.OrderDetail" SelectMethod ="GetThisUserLicense" to populate
it.
The code behind is:
Public Function GetThisUserLicense() As IQueryable(Of OrderDetail)
Return UserLicenseDetails_GetData.AsQueryable
End Function
Public Function UserLicenseDetails_GetData() As IList(Of OrderDetail)
Dim list As New List(Of OrderDetail)()
Dim ThisUser As String = User.Identity.Name
Dim ThisUserLicenseInfo As New OrderDetail()
Dim pdb As New LicenseContext
If Not ThisUser = "" Then
Try
Dim userLicense = (From c In pdb.OrderDetails Where c.Username = ThisUser AndAlso c.CategoryId = 2 Select c).LastOrDefault
If userLicense IsNot Nothing Then
License.Visible = True
ThisUserLicenseInfo.InitDate = CType(userLicense.InitDate, Date)
ThisUserLicenseInfo.ExpDate = CType(userLicense.ExpDate, Date)
ThisUserLicenseInfo.UnitPrice = CType(userLicense.UnitPrice, String)
ThisUserLicenseInfo.Credit = CType((DateDiff(DateInterval.Day, ThisUserLicenseInfo.InitDate, ThisUserLicenseInfo.ExpDate) * ThisUserLicenseInfo.UnitPrice
/ 365), String)
Else
License.Visible = False
End If
list.Add(ThisUserLicenseInfo)
Catch exp As Exception
Throw New Exception("ERROR: Unable to find User License - " & exp.Message.ToString(), exp)
End Try
Else
End If
Return list
End Function
The code chokes on trying to retrieve the record from the table OrderDetails:
Dim userLicense = (From c In pdb.OrderDetails Where c.Username = ThisUser AndAlso c.CategoryId = 2 Select c).LastOrDefault
The error is:
LINQ to Entities does not recognize the method 'LabEle3.OrderDetail LastOrDefault[OrderDetail](System.Linq.IQueryable`1[LabEle3.OrderDetail])' method, and this method cannot be translated into a store expression.
The line checks out with intellisense.
The relevant Class definitions are:
Imports System.Data.Entity
Public Class LicenseContext
Inherits DbContext
Public Sub New()
MyBase.New("LabEle3")
End Sub
Public Property OrderDetails As DbSet(Of OrderDetail)
End Class
And:
Public Class OrderDetail
Public Property OrderDetailId() As Integer
Public Property OrderId() As Integer
Public Property Username() As String
Public Property ProductId() As Integer
Public Property Quantity() As Integer
Public Property UnitPrice() As Nullable(Of Double)
Public Property CategoryId() As Integer
Public Property ProductName() As String
Public Property IPaddress() As String
Public Property Seats() As Int16
Public Property InitDate() As Date
Public Property ExpDate() As Date
Public Property Credit() As Nullable(Of Double)
End Class
The table T-SQL is:
CREATE TABLE [dbo].[OrderDetails] (
[OrderDetailId] INT IDENTITY (1, 1) NOT NULL,
[OrderId] INT NOT NULL,
[Username] NVARCHAR (MAX) NULL,
[ProductId] INT NOT NULL,
[Quantity] INT NOT NULL,
[UnitPrice] FLOAT (53) NULL,
[CategoryId] INT NOT NULL,
[ProductName] NVARCHAR (MAX) NULL,
[IPaddress] NVARCHAR (MAX) NULL,
[Seats] SMALLINT NOT NULL,
[InitDate] DATE NOT NULL,
[ExpDate] DATE NOT NULL,
[Credit] FLOAT (53) NULL,
CONSTRAINT [PK_dbo.OrderDetails] PRIMARY KEY CLUSTERED ([OrderDetailId] ASC),
CONSTRAINT [FK_dbo.OrderDetails_dbo.Orders_OrderId] FOREIGN KEY ([OrderId]) REFERENCES [dbo].[Orders] ([OrderId]) ON DELETE CASCADE
);
GO
CREATE NONCLUSTERED INDEX [IX_OrderId]
ON [dbo].[OrderDetails]([OrderId] ASC);
I think the table datatypes match the datatypes of the OrderDetail Class definition. Why can’t LINQ make sense of the request for data? Any help would be greatly appreciated.
error "LINQ to Entities does not recognize the method" when trying to retrieve record for DetailsView in VB code behind
