How do I edit the properties of controls made using QTCreator in Slot declaration?

I made a form using QTCreator. Then I change some of its properties in class constructor like

ui->cancelButton->hide();

It work. Now I declare a custom slot in header file & tried to use controls' properties in Slot implementation in class file (i.e .cpp) like

oldName = lineEDit->text();

but I get error msg

error: 'LineEdit' was not declared in this scope      

then I tried like

oldName = ui->nameLine->text();

b开发者_运维问答ut it gives same error. How do I use controls' properties in Slots declaration or other functions when I made UI using Designer ??

EDIT: SLOT SOURCE

void addressbook::addContact()
 {
     oldName    = ui->nameLine->text();  //nameLine->text();
     oldAddress = ui->addressText->toPlainText(); //addressText->toPlainText();

     nameLine->clear();
     addressText->clear();

     updateInterface(AddingMode);
 }

if you creating class Test it would produce 4 files:

    1) test.h - your class header 
    2) test.cpp - your implementation
    3) test.ui - form descriptor
    4) ui_test.h - file generated from form descriptor,
 containing cpp code to create it.

test_ui.h has a class declaration inside, with the set of members with types and names of objects you put on form. Ui::TestClass

your main class will have it as private member

private:
    Ui::TestClass ui;

so if you want to adress form elements do it as ui->ObjectNameFromForm

And - have a look onto your ui_*.h classes, it is normal cpp code, and after researching them you may understand much more clear how forms works.