I'm trying to use and virtual column in one of my Entities.  The issue I'm experiencing is that whenever the virtual field (CustomerNote) is updated on my form, the Set gets called as it should (with appropriate value) but the SetColumn call fails (with no error message).  The virtual column's value is never set to the new value.  Am I doing something incorrectly?  Is what I'm trying to do even supported?  The initial GetColumn call works perfectly fine by the way.  I realize I could probably remove the column from the GetProspect call and replace it in the Property Get/Set, but I'd prefer to grab it from the database in once call vs. two.

Here's the code:

1    'In my Custom Entity:        
2    
3    	Protected Overloads Overrides Function GetLocalBindingProperties() As List(Of EntitySpaces.Core.esPropertyDescriptor)
4                Dim props As New List(Of EntitySpaces.Core.esPropertyDescriptor)
5    
6                props.Add(New EntitySpaces.Core.esPropertyDescriptor(Me, "CustomerNote", GetType(String)))
7    
8                Return props
9            End Function
10   
11   	Public Property CustomerNote() As String
12               Get
13                   Return Me.GetColumn("CustomerNote").ToString
14               End Get
15               Set(ByVal value As String)
16                   Me.SetColumn("CustomerNote", value)
17               End Set
18           End Property

 Code:

1    'My Data Access code to fill a Prospect Entity
2    
3        Public Function GetProspect(ByVal ProspectID As Integer) As BusinessObjects.Prospect Implements IDataAccess.GetProspect
4            Dim p As New BusinessObjects.ProspectQuery("p")
5            Dim c As New BusinessObjects.CustomerQuery("c")
6    
7            p.Select(p)
8            p.Select(c.Note.As("CustomerNote"))
9            p.InnerJoin(c).On(p.CustomerID = c.CustomerID)
10           p.Where(p.ProspectID.Equal(ProspectID))
11   
12           Dim Prospect As New BusinessObjects.Prospect
13           Prospect.Load(p)
14   
15           Return Prospect
16       End Function

Totally understand that I need to handle the Save separately.  I didn't include that section of code because immediately after the "Set" (line 16 of the 1st code snippet), I check the value of CustomerNote and it's the original value that was read in from the call to GetProspect.  I am sure I'm doing something incorrect somewhere along the lines because the "value" parameter being passed in to the Set is correct.  It's just that checking it immediately afterwards, the value isn't.  Did that make sense?

 

OK, I've made some progress with that change.  I guess my property name having the same name as the aliased field was a no-no.  I'll make sure I don't do that again.

I'm still having an issue that I'm reasonably sure you wouldn't believe me if I told you.  I'm gonna attempt to create a sample project reproducing the issue.  Of course the reliance on 3rd party UI controls (DevExpress) mucks up doing that easily, but I'll try to do it without them.

At the risk of embarrassing myself, I'll tell you real quick what the issue is.  In the click event of my Save button, I'm calling a function called what-other-than "Save".  While I'm in the click handler (btnSave_Click), my CustomerNote property returns the proper (i.e. new) value.  I have a breakpoint set on the Save function (literally on the Private Function Save line) and when I hit that line, CustomerNote shows the old value.  I obviously have a breakpoint in the Set of CustomerNote and it's absolutely not being called again.  I honestly have no clue what could be causing this seemingly bizarre behavior.  The only thing I could think of is there's some weird binding issue going on.  The Prospect object is bound to a BindingSource and the CustomerNote field is set up properly in the IDE.

1        Private Sub btnSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSave.Click
2            SaveResult = Save()
3    
4            Select Case SaveResult
5                Case Enums.EditResultType.Failed
6                    Exit Sub
7    
8                Case Else
9                    If SaveResult <> Enums.EditResultType.NoChanges Then
10                       If CallingForm.Name = "ProspectList" Then CType(CallingForm, ProspectList).FillData()
11                   End If
12           End Select
13   
14           Me.Close()
15       End Sub

1        Private Function Save() As Enums.EditResultType
2            'TODO: lookup newly added customer name and see if there's a match
3            Dim SomethingChanged As Boolean = IsDirty
4    
5            Try
6                DataAccessFactory.GetDataAccess.SaveProspect(Prospect, Appt)
7    
8            Catch ex As Exception
9                HandleError(ex, True)
10               Return Enums.EditResultType.Failed
11   
12           End Try
13   
14           If Not SomethingChanged Then
15               Return Enums.EditResultType.NoChanges
16           Else
17               Return Enums.EditResultType.Saved
18           End If
19       End Function

The saga continues.  I was unsuccessful created a test project because I'm receiving an obscure error while performing the join (Value cannot be null. Parameter name: key in GetProviderMetadata).  I have to assume I'm just blind at this point because I don't see what's causing that.

That being said, I tried 2 other things in my real project.  First I tried to use the .Query.es.QuerySource trick to use a view to load my object.  I was 99.9% certain the results would be the same as constructing the query using the dynamic API.  I was correct.

Next I tried to just do away with the "data-bound" virtual column and just use a private variable within the my custom Prospect object.

I replaced:

1            'Public Property CustomerNote() As String
2            '    Get
3            '        Return Me.GetColumn("Note").ToString
4            '    End Get
5            '    Set(ByVal value As String)
6            '        Me.SetColumn("Note", value)
7            '    End Set
8            'End Property
9    
10           Public Property CustomerNote() As String
11               Get
12                   If _CustomerNote = Nothing Then
13                       Dim c As New BusinessObjects.Customer
14                       c.LoadByPrimaryKey(Me.CustomerID.Value)
15                       _CustomerNote = c.Note
16                   End If
17   
18                   Return _CustomerNote
19               End Get
20               Set(ByVal value As String)
21                   _CustomerNote = value
22               End Set
23           End Property

This works perfectly well.  I should be happy that I have things functioning properly but I'd really like to understand if my original gameplan is a viable one since it makes a whole lot more sense to me.  The major negative to this particular approach is that I'll be making an extra  round-trip to the database unnecessarily (assuming the .GetColumn/.SetColumn method would work of course).

Maybe if I'm less blind tomorrow, I'll be able to troubleshoot the mapName being Null error in my sample project and be able to make more sense of it at that point.  If you have any suggestions, I'm all ears.  Thanks.
 

The mapName issue sounds like a config error. Unless you are using Multi-provider mode and MetadataMaps, then check that the mapName is "esDefault":

providerMetadataKey="esDefault"

As to binding, I was able to duplicate the issue using our test db, a DataGridView (no 3rd party control), and an entity bound to a BindingSource. Unfortunately, the behavior is so bizarre, I do not have a better work-around for you than the one you've already come up with.

First, I took the custom entity code from your original post (8244), and put it in my custom CustomerGroup entity class.

I added this variable to my Form1 class:

Dim custGroup As New CustomerGroup()

Here is my Form1_Load:

Dim cgq As New CustomerGroupQuery("cg")
Dim gq As New GroupQuery("g")

cgq.Select(cgq)
cgq.Select(gq.Notes.As("CustomerNote"))
cgq.InnerJoin(gq).On(cgq.GroupID = gq.Id)
cgq.Where(cgq.GroupID.Equal("10001"))

custGroup.Load(cgq)

BindingSource1.DataSource = custGroup
DataGridView1.DataSource = BindingSource1

I kept ButtonSave_Click very simple:

DataGridView1.EndEdit()
BindingSource1.EndEdit()
Console.WriteLine(custGroup.CustomerNote)

Strange behavior #1: As you pointed out, when the form loads, the CustomerNote contains "Some notes" from the database. When I change it to "Note one", and click the Save button it reverts back to the old value. Stepping through SetColumn in the Property, I see the Row value change, but the instant I step out of the settor, it reverts back to its old value.

Strange behavior #2: My Save does not have a Me.Close(), so I typed "Note two", clicked the Save button, and this time it stuck. All subsequent changes were retained. When I closed the Form and re-opened it, the first change got lost, but all the rest were OK.

Strange behavior #3: If I change the object to a collection:

Dim custGroup As New CustomerGroupcollection()

and this line in the Save:

Console.WriteLine(custGroup(0).CustomerNote)

and leave everything else the same. Then the change works the first time, and every time thereafter, no problems.

I tried some variations, eliminating the BindingSource, calling custGroup.EndEdit(), etc. Nothing helped. I was also able to duplicate this in our C# test app, so it is not a C# vs. VB thing. All I can say at this point is that we are still working on it.