Creates a drop down list SelectList containing null, Yes, No.
public static SelectList YesNoList(bool allowNull = true,
YesNo selectedValue = YesNo.Null)
Does the first item contain a null or blank entry, or restrict the option to purely Yes and No.
The selected option of the SelectList to show the first time the list is displayed. Any posted back values will automatically show the selected value so no need to set this option again.
ViewBag.YesNo = SiUtil.YesNoList();