XML Feeds
In an ICollection(of T) you have a contains method to see if your collection has the requested element in it. But if you want to look for Multiple elements, you have to resort to making predicates (and we all know how ugly those get).
So why didn’t MS implement ContainsAny (OR) and/or ContainsAll (AND). I couldn’t think of a good reason, so I made them myself. They are perhaps a bit over easy and not very performance friendly but they work.
Here are the extension methods.
- <Extension()> _
- Public Function ContainsAny(Of T)(ByVal collection As ICollection(Of T), ByVal Parameters As ICollection(Of T)) As Boolean
- For Each parameter In Parameters
- If collection.Contains(parameter) Then
- Return True
- End If
- Next
- Return False
- End Function
- <Extension()> _
- Public Function ContainsAll(Of T)(ByVal collection As ICollection(Of T), ByVal Parameters As ICollection(Of T)) As Boolean
- For Each parameter In Parameters
- If Not collection.Contains(parameter) Then
- Return False
- End If
- Next
- Return True
- End Function
They are generic, so you can use them in most places.
Here is an example how it works.
- Imports System.Runtime.CompilerServices
- Imports System.Net.NetworkInformation
- Module Module1
- Sub Main()
- ShowNetworkInterfaces()
- Console.ReadLine()
- End Sub
- Public Sub ShowNetworkInterfaces()
- Dim computerProperties As IPGlobalProperties = IPGlobalProperties.GetIPGlobalProperties()
- Dim nics As NetworkInterface() = NetworkInterface.GetAllNetworkInterfaces()
- If nics Is Nothing OrElse nics.Length < 1 Then
- Console.WriteLine(" No network interfaces found.")
- Exit Sub
- End If
- For Each adapter As NetworkInterface In nics
- Dim properties As IPInterfaceProperties = adapter.GetIPProperties()
- Console.WriteLine(adapter.Name)
- For Each ip As System.Net.IPAddress In properties.DnsAddresses
- Console.WriteLine("DNS server : {0}", ip.ToString)
- Next
- Next
- Dim _list As New List(Of System.Net.IPAddress)
- _list.Add(New System.Net.IPAddress(New Byte() {192, 168, 1, 2}))
- _list.Add(New System.Net.IPAddress(New Byte() {192, 168, 1, 3}))
- Dim result = From n In nics Where n.GetIPProperties.DnsAddresses.ContainsAny(_list)
- Console.WriteLine(result.Count)
- result = From n In nics Where n.GetIPProperties.DnsAddresses.ContainsAll(_list)
- Console.WriteLine(result.Count)
- Console.WriteLine()
- End Sub
- <Extension()> _
- Public Function ContainsAny(Of T)(ByVal collection As ICollection(Of T), ByVal Parameters As ICollection(Of T)) As Boolean
- For Each parameter In Parameters
- If collection.Contains(parameter) Then
- Return True
- End If
- Next
- Return False
- End Function
- <Extension()> _
- Public Function ContainsAll(Of T)(ByVal collection As ICollection(Of T), ByVal Parameters As ICollection(Of T)) As Boolean
- For Each parameter In Parameters
- If Not collection.Contains(parameter) Then
- Return False
- End If
- Next
- Return True
- End Function
- End Module
And this is the result:
Local area connection
DNS server : 192.168.1.2
DNS server : 192.168.1.3
Local area connection 2
DNS server : 192.168.1.2
DNS server : 192.168.1.3
Local area connection 3
DNS server : 192.168.1.2
DNS server : 192.168.1.3
3
0
These are not the exact results for my machine but you get the point.
It seems to work ;-)
