Is IP Addres Vaild

[BenJones]

Hi I needed a function to check if a IP was valid and came up with this little bit of code, It's not perfect but seems to do what I needed it for
anyway I left it here as I thought it maybe of some use to someone else. Anyway comments and suggestions welcome.

Public Function IsIPAddress(ByVal Source As String) As Boolean
        Dim Temp() As String = Source.Split(".")
        Dim Slots(3) As Integer
        Dim Vaild As Boolean = True
 
        'Must be 3 pairs
        If ((Temp.Count - 1) = 3) Then
            Try
                'Get ip pairs
                Slots(0) = Integer.Parse(Temp(0))
                Slots(1) = Integer.Parse(Temp(1))
                Slots(2) = Integer.Parse(Temp(2))
                Slots(3) = Integer.Parse(Temp(3))
                'Check for vaild numbers in range of 0..255
                For x As Integer = 0 To Slots.Count - 1
                    'Check if less than zero.
                    If Slots(x) < 0 Then
                        Vaild = False
                        'Check if more than 255
                    ElseIf Slots(x) > 255 Then
                        Vaild = False
                    End If
                Next x
            Catch ex As Exception
                Return False
            End Try
        Else
            'Set flag falue.
            Return False
        End If
 
        Return Vaild
    End Function
 
    Private Sub cmdTest_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdTest.Click
        Dim Viald As Boolean = False
        'Test 1
        Viald = IsIPAddress("127.0.0.1") 'Vaild
        MessageBox.Show(Viald, "IP-TEST", MessageBoxButtons.OK, MessageBoxIcon.Information)
        'Test 2
        Viald = IsIPAddress("256.0.0.1") 'Invaild
        MessageBox.Show(Viald, "IP-TEST", MessageBoxButtons.OK, MessageBoxIcon.Information)
    End Sub

[BlindSniper]

System.Net.IPAddress.TryParse() ?
But it's still good to know how to do these things by hand. I rewrote the sin function once just to understand how it worked.

[dbasnett]

FYI:

    Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
        Debug.WriteLine("")
        Debug.WriteLine(IsIPv4Address("192.168.255.0"))
        Debug.WriteLine(IsIPv4Address("192.168.255")) 'note that this parses
        Debug.WriteLine(IsIPv4Address("192.168.255.256"))
    End Sub

    Public Function IsIPv4Address(ByVal ipStr As String) As Boolean
        Debug.WriteLine(">>> " & ipStr)
        'using System.Net.IPAddress.TryParse method
        Dim ipAddr As System.Net.IPAddress = Nothing
        If System.Net.IPAddress.TryParse(ipStr, ipAddr) Then
            Debug.WriteLine(ipAddr.ToString)
        Else
            Debug.WriteLine("Parse failed")
        End If

        'check each octet method
        Dim Temp() As String = ipStr.Split("."c)
        Dim isValid As Boolean = True
        If Temp.Count = 4 Then
            For Each s As String In Temp
                Dim octet As Integer
                If Not (Integer.TryParse(s, octet) AndAlso octet >= 0 AndAlso octet <= 255) Then
                    isValid = False
                    Exit For
                End If
            Next
        Else
            isValid = False
        End If
        Return isValid
    End Function

[BenJones]

Did not know about that System.Net.IPAddress.TryParse() BlindSniper will ahve to have a look
lol yer I like re-inventing the wheel to. I always like to see how something works.
Nice bit of code dbasnett will come in handy.

[dbasnett]

I am not a fan of System.Net.IPAddress.TryParse for the reason shown in the code I posted.