Is it possible to create a custom field in a BO, that is not part of the underlying DataSource,  that I can bind to?  I tried adding the following custom field to my BO.

Private mVerifyPassword As String = ""

<Browsable(False), _

BusinessFieldDisplayInEditor(), _

Description("Verify Password"), _

DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)> _

Public Property UserCF_VerifyPassword() As System.String

   Get

     Return mVerifyPassword

   End Get

   Set(ByVal value As System.String)

      If mVerifyPassword = value.Trim Then Exit Property

      mVerifyPassword = value.Trim

Me.OnFieldPropertyChanged(Me, _

 New UserFieldChangedEventArgsmVerifyPassword))

   End Set

End Property

I can bind to it in the designer but when I go to run the program I get the following error:

BusinessLayerException

                An error occurred while refreshing the data from field 'UserBO.UserCF_VerifyPassword' to property 'Text' on control 'txtVerifyPassword.'  Are you missing FieldPropertyDescriptor for a custom property?

ArgumentException

                Cannot bind to the property or column UserCF_VerifyPassword on the DataSource.

Parameter name: dataMember

Source     : MicroFour StrataFrame Business

Stack Trace:

   at System.Windows.Forms.BindToObject.CheckBinding()

   at System.Windows.Forms.BindToObject.SetBindingManagerBase(BindingManagerBase lManager)

   at System.Windows.Forms.Binding.SetListManager(BindingManagerBase bindingManagerBase)

   at System.Windows.Forms.ListManagerBindingsCollection.AddCore(Binding dataBinding)

   at System.Windows.Forms.BindingsCollection.Add(Binding binding) ...

-Larry

I should have mentioned in my previous post that the custom field that I want to bind to is not ReadOnly. Binding of ReadOnly custom fields as shown in the getting started guide works fine.

I finally figured out that in order to get two way binding I needed to add a FieldPropertyDescriptor object for the custom field and add it to the PropertyDiscriptorDictionary.  What I’m not sure of at this point is what other dictionaries I need to add the field to since I’m not sure how and where each one is used.

-Larry

In the documentation an example is provided for creating a custom property descriptor using ReflectionPropertyDescriptor(). However the doc says for a real-world application you should create your own class. Can you provide an example or documentation describing what actually must be in a custom field descriptor class? 

-Larry

You can create your own class if you need to do some more sophisticated processing and I will show you an example of that, but to do eveything youa re attempting to do you can use a ReflectionpropertyDescriptor and place code similar to this in your business object:

''' <summary>
''' Specify the custom property descriptors
''' </summary>
''' <returns></returns>
''' <remarks></remarks>
Protected Overrides Function GetCustomBindablePropertyDescriptors() As MicroFour.StrataFrame.Business.FieldPropertyDescriptor()

'-- Create and return a new array of FieldPropertyDescriptor
' objects that contains the ReflectionPropertyDescriptor
' for the UserCF_VerifyPassword field.
Return New MicroFour.StrataFrame.Business.FieldPropertyDescriptor() { _
New MicroFour.StrataFrame.Business.ReflectionPropertyDescriptor("UserCF_VerifyPassword", GetType(YourBO)), _
New MicroFour.StrataFrame.Business.ReflectionPropertyDescriptor("YourNextCustomField", GetType(UsersBO))}

End Function

Creating a Custom Class

To create a custom class it would look something like this which is what we do through the BO Mapper when the field is not custom or overwritten with custom code.

''' <summary>
''' A PropertyDescriptor class used to Get and Set the value of the UserCF_VerifyPassword property.
''' </summary>
''' <remarks></remarks>
Private Class UserCF_VerifyPassword_Descriptor
    Inherits MicroFour.StrataFrame.Business.FieldPropertyDescriptor

Public Sub New()
     MyBase.New("UserCF_VerifyPassword")
End Sub

Private _PropertyType As System.Type = GetType(System.String)

Public Overrides Function GetValue(ByVal component As Object) As Object
    Return CType(component, YourBO).UserCF_VerifyPassword
End Function

Public Overrides Sub SetValue(ByVal component As Object, ByVal Value As Object)
    CType(component, YourBO).UserCF_VerifyPassword = CType(Value, System.String)
End Sub

Public Overrides ReadOnly Property PropertyType() As System.Type
    Get
        Return Me._PropertyType
    End Get
End Property

Public Overrides ReadOnly Property ComponentType() As System.Type
    Get
        Return _ComponentType
    End Get
End Property

End Class

Once the class is created, you still need to overwrite the GetCustomBindablePropertyDescriptors() method add return the collection including your new class:

Return New MicroFour.StrataFrame.Business.FieldPropertyDescriptor() { _
New UserCF_VerifyPassword_Descriptor(), _
New MicroFour.StrataFrame.Business.ReflectionPropertyDescriptor("YourNextCustomField", GetType(UsersBO))}

Thanks for the help. Copying and modifying the code from the designer file makes it real easy.

-Larry