Visual Basic

Imports System.Io
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Public Shared Function CountLinesInFile(ByVal filepath As String) As Integer
    If File.Exists(filepath) Then
        Using fs As New StreamReader(filepath)
            Dim count As Integer = 0
            While Not fs.EndOfStream
                fs.ReadLine()
                count += 1
            End While
            Return count
        End Using
    End If
    Throw New FileNotFoundException(filepath)
End Function