title: C# how to pass the value of form3 back to form1
body: <p>This question is the followup to the following question:
  <a href="https://stackoverflow.com/questions/12795668/c-sharp-text-dont-display-on-another-form-after-double-clicking-an-item-in-list">C# Text don&#39;t display on another form after double clicking an item in listbox</a></p>
  
  <p>Now I have typed my value in the textbox of form3. How am I going to pass back the value to form1 to show it in the listbox10 after pressing "OK" in form3? Below is my form3 coding but it don't work:</p>
  
  <pre><code>private void button1_Click(object sender, EventArgs e)
  {   
      //This is the coding for "OK" button.
      int selectedIndex = listBox10.SelectedIndex;
      listBox10.Items.Insert(selectedIndex, textBox1.Text);
  }
  </code></pre>