VB.NET - Getting String Between 2 Strings

Public Function GetStringBetween(ByVal Haystack As String, ByVal StartSearch As String, ByVal EndSearch As String) As String
        Dim rx As New Regex(StartSearch & "(.+?)" & EndSearch)
        Dim m As Match = rx.Match(Haystack)
        If m.Success Then
            Return m.Groups(1).ToString()
        Else
            Return False
        End If
    End Function

Public Function GetBetween(ByVal haystack As String, ByVal needle As String, ByVal needle_two As String) As String
        Dim istart As Integer = InStr(haystack, needle)
        If istart > 0 Then
            Dim istop As Integer = InStr(istart, haystack, needle_two)
            If istop > 0 Then
                Try
                    Dim value As String = haystack.Substring(istart + Len(needle) - 1, istop - istart - Len(needle))
                    Return value
                Catch ex As Exception
                    Return ""
                End Try
            End If
        End If
        Return ""
    End Function

Dim Haystack As String = "<input type=""hidden"" name=""testsubmit"" id=""testsubmit"" value=""findme""  />"
Dim FindIt As String = GetBetween(Haystack, "id=""testsubmit"" value=""", """ ")
MessageBox.Show(FindIt)

<input type="hidden" name="testsubmit" id="testsubmit" value="findme"  />

Dim needle as string = "name="""
Dim needle_two as string = """ id="""
dim strName as string = GetBetween(strHTML, needle, needle_two)