vb.net - iterating by controls enclosing object

i have form "clear" button.

when user clicks "clear", i wish pristine value manifest elements form. box date controls, i wish reset tide date.

all controls contained panel.

right now, i'm doing next code. there an easier proceed manually checking any control type? slight seems excessively unwieldy.

to matters worse, method recursively pristine controls inside sub-containers (i.e., organisation box within panel) i have repeat whole monster an overloaded "groupbox" version.

edit: interjection your suggestions, next formula severely simplified.

private servant btnclear_click(byval sender system.object, byval e system.eventargs) handles btnclear.click
    'user clicks clear, pristine controls within panel
    clearallcontrols(panmid, true) 'true indicates yes, i wish recurse by sub-containers
end sub

clearallcontrols(byref enclosing panel, discretionary recurse boolean = true)   
  'clear controls within enclosing object
  'if "recurse" true, following also pristine controls within any sub-containers
  low ctrl control
  any ctrl container.controls
      (ctrl.gettype() gettype(textbox)) then
          low txt textbox = ctype(ctrl, textbox)
          txt.text = ""
      finish if
      (ctrl.gettype() gettype(checkbox)) then
          low chkbx checkbox = ctype(ctrl, checkbox)
          chkbx.checked = false
      finish if
      (ctrl.gettype() gettype(combobox)) then
          low cbobx combobox = ctype(ctrl, combobox)
          cbobx.selectedindex = -1
      finish if
      (ctrl.gettype() gettype(datetimepicker)) then
          low dtp datetimepicker = ctype(ctrl, datetimepicker)
          dtp.value = now()
      finish if

      recurse then
          (ctrl.gettype() gettype(panel)) then
              low pnl quarrel = ctype(ctrl, panel)
              clearallcontrols(pnl, recurse)
          finish if
          ctrl.gettype() gettype(groupbox) then
              low grbx groupbox = ctype(ctrl, groupbox)
              clearallcontrols(grbx, recurse)
          finish if
      finish if
  next
end sub

@theraccoonbear: i your suggestion, nonetheless i change chapter this:

private servant clearallcontrols(byref controls controlcollection, discretionary byval recurse boolean = true)

then line gives me "unable ban vigilant form 'controlcollection' form 'controlcollection'.":

  clearallcontrols(panmid.controls)