Error 91: object variable or with block varaible not set

"Error 91: object variable or with block varaible not set"

i am getting the above error while retrieving the index of selected row in listview

please help me out

Private Sub ListPersons_DblClick()

Dim row As Integer
Dim item As ListItem
Dim personid As Double
Dim bsuccess As Boolean
Dim msName As String


'Listpersons is the name of listview
row = ListPersons.SelectedItem.index
personid = ListPersons.ListItems(row)

End Sub

ListPersons.SelectedItem.index will give you that error if there is no item selected or listview does not have any item.

ListPersons.ListItems(row) will return a listitem, that cannot be assigned to a number.

the listview is not empty and i have selected an item too
i dont think tht's the problem
thank u