for (int i = 1; i <= 31; i++) { ddl.Items.Add(i.ToString()); }
DropDownList ddl = new DropDownList(); for(int i=1; i<=31; i++) ddl.Items.Add(New ListItem(i.ToString()));
Dim ddl As DropDownList = new DropDownList(); for i as Integer =1 to 31 ddl.Items.Add(New ListItem(i.ToString())) next i
this.Controls.Add(ddl);