How to search in listview

I am trying to create a Loop that will read through the information on my ListView through the SubItem to find the text that matches the text in my Textbox whenever I hit the search button and Focuses the listbox onto the matched text. Below is what I have but it keeps telling me that the value of string cannot be converted. I am also pretty sure that my numbers wont loop correctly but I am not really sure how to cause them to loop endlessly till end of statement.

    Dim T As String    T = Lines.Text    For r As Integer = 0 to -1        For C As Integer = 0 to -1            If List.Items(r).SubItems(C).Text = Lines.Text Then                List.FocusedItem = T            End If        Next    NextEnd Sub