i am using vb.net with cr 8.0

i have inserted the cr viewer in form 10 but i need the value from the textbox1 of form7 plz tell me how to get that , i need to insert it inti the record selection formula.
VB Code:
  1. Dim oapp As CRAXDRT.Application

  2. Dim rpt As CRAXDRT.Report

  3.  
  4. Set oapp = New CRAXDRT.Application

  5. cr1.ReportSource = rpt

  6.  
  7. rpt.RecordSelectionFormula = "{DATA2.gba}=" & val(Form7.Textbox1.Text) & ""

i have a combobox which on load of the form takes the values from the database table now waht i want is that if i press any alphabet say "k" then combobox must open and all the values in the combo box starting with k must be shown