AddChildItemBinded & ReadOnly Properties

I'm having difficulty updating the value displayed by a propertygrid item which is bound to a readonly property.

Here is the code I used to add the bound item:

Set xpgItem = xpgCategory.AddChildItemBinded(PropertyItemNumber, oItems, "Count")
xpgItem.ReadOnly = True

If the value of oItems.Count subsequently changes, I need the PropertyGrid to display the new value, so (as per the documentation) I explicitly update the PropertyGridItem value with the contents of the variable:

wndPropertyGrid.FindItem("Count").Value = oItems.Count

However, when I do this, I get the following run-time error:

Run-time error '451': Property let procedure not defined and property get procedure did not return an object

Any ideas what I'm doing wrong?

Hi Oleg

TypeName(wndPropertyGrid.FindItem("Count")) = IPropertyGridItem
wndPropertyGrid.FindItem("Count").value = 1
oItems.Count = 2
TypeName(oItems) = clsItems

If I don't set the ReadOnly flag on the PropertyGridItem, then I get the same error when programmatically setting the value, or by typing the new value into the propertygrid using the keyboard.

The error message that appears is technically correct. oItems.Count is a Property, of type Long, defined with a Get and no Let or Set. (i.e. the Count property is a read only value which is set based on other properties within the oItems object)

Private colItems As Collection
Public Property Get Code() As Long
    If Not colItems Is Nothing Then
        Count= colItems.Count
    Else
        Counts= 0
    End If
End Property

Any other ideas, or should I just revert to a regular child item as I am only displaying this value for informational purposes and have no real need for this property to be bound?