Matches to list or set

how to convert matches output to set ?
System.Text.RegularExpressions.Regex.Matches(Input String,Regex pattern)

output of this is Out_Matches = MatchCollection(3) { [26.11.2020 ], [26.11.2020 ], [27.11.2020 ] }

i need set (“26/11/2020”, “27/11/2020”) set in dd/MM/yyyy format

Out_Matches.Select(Function(x) x.Value).ToList
list_string = x.value).tolist — this is not working

Out_Matches.Select(Function(x) x.Value).ToList
has to be casted befor using the select method

Out_Matches.Cast(Of Match).Select(Function(x) x.Value).ToList

Ensure System.Text.RegularExpressions is imported on the namespaces