C Sharp :: Changing If Statement During Runtime When New Control Is Added

This is for excel . I have a form with 2 combobox and 1 textbox ...

combo 1 : user can select a column ; let say column A
combo 2 : user can select an operator ; let say = (equal)
textbox : user can enter value ; let say 2

so my code is like

if (column A == tb.text) {
    execute code here
}

but the problem i have is during run time i allow user to add more controls to the form

if ((column A == tb.text) && (column B == tb2.text)) && //may be more if user add {
   execute code here 
}

how do i handle this 'cause, how many will the user add to it, and the code should change when user add new control to it.