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c# - SelectList with a null selection

I have a bunch of drop down lists in my view, such as this one:

@Html.DropDownListFor(model => model.Process, Model.ProcessList)

They all take in a SelectList based on data from a database table like this:

ProcessList = new SelectList(_db.Processes, "ID", "Name");

where _db.Processes returns a ObjectSet<Process>.

The issue I have is that sometimes the property that is set by the drop down list can be no selection, i.e. null. How can I add a null selection to the SelectList>

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@Html.DropDownListFor(model => model.Process, Model.ProcessList,"--Select Process--")

The above line would add --select process-- at the top of select list and if this value is selected, empty string will be posted and bound property will be set to null (Process in this case)


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