asp.net mvc 3 - How to create default custom value of dropdownlist -

i want customize default value of dropdownlist, having value of "select item" instead of value exist database.

view

 @html.editorfor(m => m.vendor) 

model

 [uihint("sellerdropdown")]     public mdl.vendor vendor{ get; set; }  

try this:

@html.dropdownlistfor(m => m.vendor, myselectlist, "select item");