I am having a trouble while trying to create an entity with a custom view modeled create form. Below is my custom view model for Category Creation form.
publ
You could use editor templates. Put your ascx control in ~/Views/Shared/EditorTemplates/SomeControl.ascx. Then inside your main View (aspx page) include the template like so (assuming your view is strongly typed to CategoryFormViewModel):
<%= Html.EditorForModel("SomeControl") %>
instead of
<% Html.RenderPartial("SomeControl", Model) %>