Anyone knows how to get the line number of a specific line in a .txt file?

Code:
Dim c As Integer = 1
Dim sr As New System.IO.StreamReader(onlinefileversion)
Dim line As String = String.Empty

Public Sub versioncheck()
        line = sr.ReadLine.IndexOf(myfileversion)
        Do While (Not line Is Nothing)
            If line.Contains(myfileversion) Then
                MsgBox("Exitsts")
            Else
                MsgBox("Does not exist")
            End If
            line = sr.ReadLine()
            c = c + 1
        Loop
    End Sub
The code reports if the X version exists in a .txt file, but now I also need the lines number for the program to work correctly.
If my post is unclear, tell me and i will describe it a bit more.