settings comes in effect when the DropDownList is bound to a model, it has no effect on a DropDownList that does not have a value binding applied.
When the DropDownList is bound to a field of a model, the valuePrimitive
setting determines the binding behavior of the DropDownList. If set to true
, the underlying Grid model field will be updated with the selected item value field. If set to false, the Grid model field will be updated with the entire selected data item (with all its properties).
You can see, in the following example, that even a regular DropDownList, when put in an MVVM binding scenario needs the valuePrimitive
setting to configure its binding behavior:
The value binding behavior of list widgets (DropDownList, ComboBox, etc.) is explained in this article:
View-Model Fields with Value Field of Primitive Value
This behavior has been the default for quite some time now and changing it would be a breaking change in a lot of customer projects.