Find all indices of a string in text channel

I have text channels; each has some values containing the word "Shutdown". I would like to determine all the indices of those values. I tried ChnFind method but it was not successful. Please check the following code:

  for each oGrp in Data.Root.ChannelGroups
    ChnString = oGrp.Channels("Description").GetReference(eRefTypeNameName)
    Ind = 1
    while Ind <> 0 
      Ind = ChnFind("Ch(ChnString)" & " contains " & """Shutdown""", Ind)
    wend
  next 

PNo method can do the right job but it can only detect the first value.

I wonder if there is a method able to search string and support wildcards. It will be very helpful in this case. 

Thank you