Question

I’m experimenting with ASP.NET MVC2, in particular viewmodels and partials. My question is: Is it ‘valid’ or ‘right’ to have your partials strongly typed against an interface and the have your viewmodels implement that interface if the view uses the partial?

To illustrate, say I have a Product form partial (strongly typed against IProductFormViewModel) which is used in both the Edit and Create views. These views are strongly typed against ProductEditViewModel and ProductCreateViewModel which implement the IProductFormViewModel.

The benefit being that the corresponding POST actions for Create and Edit take ProductCreateViewModel & ProductEditViewModel objects respectively.

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Edit:
If the partial has its own dedicated viewmodel (ProductFormViewModel) and each of the ProductEditViewModel & ProductCreateViewModel expose a property of type ProductFormViewModel which is passed to the partial, then when the form is submitted the model binding of ProductEditViewModel & ProductCreateViewModel doesn’t work as the Edit and Create actions expect their respective object types…thats the reason for the approach.

Answer 1

You may have problems when your interfaces for your different partials expose the same property name e.g. name. You would then have to explicity implement the interface which would then cause problems with your model binding.

Otherwise it should work.