GetNameFromDispID, ShowPropertyPageEditor

Look up a member’s name from its dispatch ID, and show the property page that edits one property of an object.

Both procedures are declared Hidden and Restricted, so IntelliSense lists leave them out. They exist for twinBASIC’s own packages, which call them while hosting property pages; ordinary code does not need them.

GetNameFromDispID

Returns the name of the member of an object that has a given dispatch ID.

Syntax: GetNameFromDispID( Object, DispID ) As String

Object
required An object that exposes type information. An IUnknown parameter, so any object reference is accepted.
DispID
required Long. The dispatch ID (DISPID) of a member of Object.

The name comes from the object’s type information. GetNameFromDispID(x, 0) is the name of the default member and -4 that of the enumerator member, when the object has them.

Dim Table As Object = CreateObject("Scripting.Dictionary")
Debug.Print GetNameFromDispID(Table, 0)     ' Item
Debug.Print GetNameFromDispID(Table, 2)     ' Count
Debug.Print GetNameFromDispID(Table, -4)    ' _NewEnum

The call raises an error when no name can be returned:

Case Error
Object is Nothing -2147467261, Invalid pointer
Object has no type information (a Collection, for one) -2147467263, Not implemented
A member of a twinBASIC class has no such ID 5, Invalid procedure call or argument
A member of a type-library object, such as a Scripting.Dictionary, has no such ID -2147319765, Element not found.

The VB package’s PropertyPage calls it when the property sheet asks a page to edit a property by dispatch ID, to find the property’s name.

ShowPropertyPageEditor

Shows the property page that edits one property of a control.

Syntax: ShowPropertyPageEditor Caption, Object, DispID

Caption
required String. The title of the page.
Object
required An IUnknown reference to the control whose property is edited.
DispID
required Long. The dispatch ID of the property to edit.

The VB package’s ActiveX control host calls it with the control’s name, the control’s object and the property’s dispatch ID, when it is asked to edit a property that is linked to a property page. The call that shows all of a control’s property pages at once is the hidden ShowPropertyPages.

Sub EditProperty(ByVal Control As Object, ByVal PropertyDispId As Long)
    ShowPropertyPageEditor "Properties", Control, PropertyDispId
End Sub

See Also