Signal and a slot for different forms of qt

I have next code:

Code:

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ui->treeWidget->currentItem()->setText(0,ui->comboBox->currentText();

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but i want this for different forms

mainwidow.ui (treeWidget)
module.ui (comboBox)

How can i do it this in signal-slot?

Sorry for my bad english

In different forms if you've the tree widget in it then you can able to do it.....