c# - How to add two textbox value in rdlc report -

c# - How to add two textbox value in rdlc report -

in rdlc study having 3 textboxes,the first text box have total value,the sec textbox manual entry,in 3rd textbox have display sum of textbox1 , textbox2 values.i having uncertainty in how come in manual entry in rdlc study whether possible come in value @ run-time. have used look textbox3 is

=reportitems!textbox11.value + reportitems!textbox13.value

but showing #error in 3rd texbox.i working in wpf.

i see mention in illustration state need add together text box 1 , 2 , set result in 3. adding textbox 11 , 12 together... other that, spot on.

c# wpf rdlc