Find Max and Min Date in Listbox and Display in Me.Text

[norffman]

Trying to take a group of listbox strings and perform a regex to find all dates, then find the maximum and minimum date values. After that, want to harvest the results and place them into the form title, me.text. I think I'm fairly close, but for whatever reason, when I try to add the matches to the list of string, get a failure relating to no instance of list.

Sample of results in listbox where values need to be extracted:
04/18/2018 11:12 0000000 4444444 XR XR SPINE LUMBAR AP & LAT
04/18/2018 13:00 1111111 1111111 XR C-ARM<1 HR W IMAGES
04/19/2018 17:34 2222222 3333333 XR XR PICC LINE INSERTION PNL

Dim thedates As List(Of String)
            Dim sel As String
            For Each str As String In LstResults.Items
                sel &= str & " "
            Next
 
            Dim reg As Regex = New Regex("\d{1,2}\/\d{1,2}\/\d{1,4}")
            Dim matches As MatchCollection = reg.Matches(sel.ToString)
 
 
            'Getting Object Not Set to an Instance Exception
            ' Loop over matches.
            For Each m As Match In matches
                ' Loop over captures.
                For Each c As Capture In m.Captures
 
                    '''***BREAK POINT***
                    thedates.Add(c.ToString)
 
                Next
            Next
 
 
            Dim lstdates As List(Of DateTime) = thedates.[Select](Function(x) DateTime.ParseExact(x, "MM/dd/yyyy", Nothing)).ToList()
 
            Dim minDate As DateTime = lstdates.Min()
 
            Dim maxDate As DateTime = lstdates.Max()
 
            Me.Text = "SomeApp Title" & ":  " & minDate.ToString & " - " & maxDate.ToString

Much appreciated!