Dim _xmlSend As String = "<EFF_DATE>20181010</EFF_DATE><EXP_DATE>20191010</EXP_DATE>"
Dim start_Index_EFF_DATE As Integer = _xmlSend.IndexOf("<EFF_DATE>") + 9
Dim end_Index_EFF_DATE As Integer = _xmlSend.IndexOf("</EFF_DATE>") - 1
Dim index_EFF_DATE As Integer = (start_Index_EFF_DATE - end_Index_EFF_DATE)
Dim effDate = _xmlSend.Substring(index_EFF_DATE, 8)
Dim start_Index_EXP_DATE = _xmlSend.IndexOf("<EXP_DATE>") + 9
Dim expDate = _xmlSend.Substring(start_Index_EXP_DATE, 8)
Console.WriteLine("Result => " & end_Index_EFF_DATE)