pass an Object to external .dll funcion and get a changed Object

Question

hi i have an external .dll function. i need to pass i.e. TextBox object to that function so that after the called Class finishes her job, she must change i.e. TextBox.Text and get killed cant use the simple public variables. coz its about 112 objects that gonna use that Class. any suggestions? delegates? out? ref? what? stank you