Passing data between forms

Question

I have two forms. First, Form1 has a group box, some labels and a listbox. I press a button and new Form2 is opened and contains some text. I want to transfer the text in Form2 to the listbox in the Form1.

So far, what I have done is make modifier of listbox to public and then put this code in the button of Form2

Form1 frm = new Form1();
frm.ListBox.items.Add(textBox.Text);

But amazingly, this does not add any value. I thought I was mistaken with the insertion so I made the same procedure. This time, I made a label public and added textbox value to its Text property but it failed.

Any ideas?

Answer 1

Let's assume Form1 calls Form2. Please look at the code:

Form1:

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        Form2 frm = new Form2();
        frm.Show();
        frm.VisibleChanged += formVisibleChanged;


    }

    private void formVisibleChanged(object sender, EventArgs e)
    {
        Form2 frm = (Form2)sender;
        if (!frm.Visible)
        {
            this.listBox1.Items.Add(frm.ReturnText);
            frm.Dispose();
        }


    }

}

Form2:

 public partial class Form2 : Form
{

    public string ReturnText { get; set; }

    public Form2()
    {
        InitializeComponent();

    }

    private void button1_Click(object sender, EventArgs e)
    {
        this.ReturnText = this.textBox1.Text;
        this.Visible = false;

    }


}

The answer is to declare public property on Form2 and when form gets hidden. Access the same instance and retrieve the value.

Answer 2

Please avoid the concept of making any public members like you said >>i have done is make modifier of listbox to public and then in form2 in button code<< this is not a good practice,on the other hand the good one is in Brad Christie's Post,I hope you got it.