I wonder if you can throw a bit of light into this problem which I believe has something to do with custom fields in a BO. I have the following error in business object "boPUN_New" when I open up the form in the IDE that contains the BO. I can close the form and generally mess around until the form opens and I can see it the designer. boPUN_New is the datasource in a grid and I can see all the fields except my custom fields. I've used custom fields before so I have a template to follow and, as best as I can see, I've created them in this BO in the same manner as I've created them in other BO's. I've been messing around with this all day now and I'm getting no where - hopefully you can offer an insight that will help me make some progress...

TIA - Peter

Thanks for the response but I don't think that's the case. However would you mind casting your eyes over the code - maybe you can spot an error that I can't see. My set of Imports wasn't exactly the same as your example but I added in those I was missing (just in case) but that didn't make any difference.

Cheers, Peter

#Region "Custom Fields"

    ''' <summary>
    ''' OperatorName
    ''' </summary>
    ''' <remarks></remarks>
    <Browsable(False), _
     BusinessFieldDisplayInEditor(), _
     Description("OperatorName"), _
     DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)> _
    Public ReadOnly Property [Product]() As System.String
        Get
            Dim loValue As Object
            loValue = Me.CurrentRow.Item("OperatorName")
            If loValue Is DBNull.Value Then
                Return String.Empty
            Else
                Return CType(loValue, System.String)
            End If
        End Get
    End Property

    ''' <summary>
    ''' INIDescription
    ''' </summary>
    ''' <remarks></remarks>
    <Browsable(False), _
     BusinessFieldDisplayInEditor(), _
     Description("INIDescription"), _
     DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)> _
    Public ReadOnly Property [INIDescription]() As System.String
        Get
            Dim loValue As Object
            loValue = Me.CurrentRow.Item("INIDescription")
            If loValue Is DBNull.Value Then
                Return String.Empty
            Else
                Return CType(loValue, System.String)
            End If
        End Get
    End Property

    ''' <summary>
    ''' INIMaxHides
    ''' </summary>
    ''' <remarks></remarks>
    <Browsable(False), _
     BusinessFieldDisplayInEditor(), _
     Description("INIMaxHides"), _
     DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)> _
    Public ReadOnly Property [INIMaxHides]() As Nullable(Of System.Int32)
        Get
            Dim loValue As Object
            loValue = Me.CurrentRow.Item("INIMaxHides")
            If loValue Is DBNull.Value Then
                Return CType(Nothing, Nullable(Of System.Int32))
            Else
                Return New Nullable(Of System.Int32)(CType(loValue, System.Int32))
            End If
        End Get
    End Property

    ''' <summary>
    ''' INIMaxWeight
    ''' </summary>
    ''' <remarks></remarks>
    <Browsable(False), _
     BusinessFieldDisplayInEditor(), _
     Description("INIMaxWeight"), _
     DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)> _
    Public ReadOnly Property [INIMaxWeight]() As Nullable(Of System.Int32)
        Get
            Dim loValue As Object
            loValue = Me.CurrentRow.Item("INIMaxWeight")
            If loValue Is DBNull.Value Then
                Return CType(Nothing, Nullable(Of System.Int32))
            Else
                Return New Nullable(Of System.Int32)(CType(loValue, System.Int32))
            End If
        End Get
    End Property

    ''' <summary>
    ''' INIMaxArea
    ''' </summary>
    ''' <remarks></remarks>
    <Browsable(False), _
     BusinessFieldDisplayInEditor(), _
     Description("INIMaxArea"), _
     DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)> _
    Public ReadOnly Property [INIMaxArea]() As Nullable(Of System.Int32)
        Get
            Dim loValue As Object
            loValue = Me.CurrentRow.Item("INIMaxArea")
            If loValue Is DBNull.Value Then
                Return CType(Nothing, Nullable(Of System.Int32))
            Else
                Return New Nullable(Of System.Int32)(CType(loValue, System.Int32))
            End If
        End Get
    End Property

    Protected Overrides Function GetCustomBindablePropertyDescriptors() As MicroFour.StrataFrame.Business.FieldPropertyDescriptor()
        Return New MicroFour.StrataFrame.Business.FieldPropertyDescriptor() { _
             New MicroFour.StrataFrame.Business.ReflectionPropertyDescriptor( _
            "OperatorName", GetType(boPUN_New)), _
             New MicroFour.StrataFrame.Business.ReflectionPropertyDescriptor( _
            "INIDescription", GetType(boPUN_New)), _
             New MicroFour.StrataFrame.Business.ReflectionPropertyDescriptor( _
            "INIMaxHides", GetType(boPUN_New)), _
             New MicroFour.StrataFrame.Business.ReflectionPropertyDescriptor( _
            "INIMaxWeight", GetType(boPUN_New)), _
             New MicroFour.StrataFrame.Business.ReflectionPropertyDescriptor( _
            "INIMaxArea", GetType(boPUN_New))}
    End Function

#End Region

There is not a "bug" in this particular instance otherwise none of the other fields would appear.  I did not look at your code in depth yet.  Standard mapped fields work on this very same principal and through the very same attributes, etc.  So if you setup your custom property correctly it will appear just like any other field....I will look at your code in more depth when I get a chance.  Just wanted to let you know that the standard properties work the very same as a custom property when setup correctly.