Dim arrayHex As String() = {"00", "01", "02", "03", "04", "05", _
"06", "07", "08", "09", "0A", "0B", _
"0C", "0D", "0E", "0F", "10", "11", _
"12", "13", "14", "15", "16", "17", _
"18", "19", "1A", "1B", "1C", "1D", _
"1E", "1F"}
Dim test As string = "08"
Dim query = arrayHex.Select(Function(o,i) New With { .Hex = o, .Index = i}) _
.FirstOrDefault(Function(item) item.Hex = test)
If query Is Nothing
Console.WriteLine("Item not found")
Else
Console.WriteLine("Item found at index {0}", query.Index)
End If