MVC Html.DropDownList selected value being overriden by QueryString value

I am using a dropdownlist in my view like so:

@Html.DropDownList("ClientId", Model.AvailableClients, "-- None --")

Model.AvailableClients is an IEnumerable one of the item's Selected property is set to true. If in the query string for the page request includes "ClientId=" (as in its not set) MVC ignores my selected item. I assume this is because MVC is trying to be helpful and set the selected item automatically using the querystring, but I dont want this.

How can I prevent the querystring value from overriding m开发者_高级运维y item's selected value?

If the name you give your DropDownList is already the name of an element in your model then DropDownList will automatically override the selected value with the model value. If letting ClientId determine the selected value isn't an option then the only solution I know is to rename the DropDownList with a name not included in the model.

@Html.HiddenFor(m => m.ClientId)
@Html.DropDownList("ClientIdNewName", Model.AvailableClients, "-- None --", new { onchange = "ClientId.value = this.value"})

This will keep the value in ClientId without making it the default selection value.