Setting asp:DropDownList Control Value to nothing

[Greg]

I have a page that displays a DropDownList control that allows a Manager Name
to be selected from a listing of Managers for a User. So, on my main
user.aspx page, I include a DropDownList control for ManagerID. This dropdown
list provides three options to choose for managers. Right now, most users do
not have a Manager selected yet, thus the User's ManagerID value would be
null. How can I make the DropDownList control show nothing selected when the
data source value is null? I want nothing selected when no selection has been
made.

 

[Göran Andersson]

I have a page that displays a DropDownList control that allows a Manager Name
to be selected from a listing of Managers for a User. So, on my main
user.aspx page, I include a DropDownList control for ManagerID. This dropdown
list provides three options to choose for managers. Right now, most users do
not have a Manager selected yet, thus the User's ManagerID value would be
null. How can I make the DropDownList control show nothing selected when the
data source value is null? I want nothing selected when no selection has been
made.

A DropDownList always has one item that is selected.

You just have to add a "none selected" item and make that selected when
the value is null.

If the data source is a database, you would get a DbNull value. That
converts into an empty string, so if you set the value of the "none
selected" item to an empty string, it should get selected for null values.