How do I turn off validation on Html.DropDownList() when using an option label?

Question

I am passing a optionLabel into the Html.DropDownList helper (taken from this SO question):

<%=Html.DropDownList("PO.Vendor.VendorId", this.Model.Vendors, "-- add a new vendor --")%>

That produces markup with an option of value 0 with the text "-- add a new vendor --", which is exactly what I want. However, if that option is selected and posted, a validation error is thrown.

Is there way to turn off this automatic validation when using an optionLabel?

Answer 1

The code snippet that you posted doesn't have anything to do with the validation being performed. You could easily just write out all the options in the list manually and you'd still be getting the validation error.

Without seeing the code that is performing the validation, it's hard to tell you how to turn it off. If you're using the reflection-based "UpdateModel()" like in NerdDinner, you'll need to add some code to remove/change that posted value.

Wherever your validation code is, you'll have to work something out to ignore that value.