(c# + windows forms) Adding items to listBox in different class

Question

I have two classes(forms), and I would like an item from class2 to be added to listBox in class1 when I click \"Accept\" button.

I

Answer 1

Declare RentalId property on Form2. And at CarRental form (your first form) do following:

using(Form2 form2 = new Form2())
{
    if (fomr2.ShowDialog() != DialogResult.OK)
        return;

    listBox.Items.Add(form2.RentalId);
}

Implement Fomr2.RentalId property this way:

public string RentalId
{
   get { return idRental.Text; } // you don't need ToString() call
}

Then select your "Accept" button and set its DialogResult property to OK. Thus clicking on that button will close your dialog form and return DialogResult.OK.