title: Winforms in Excel add-in won't update
body: <p>I am developing an Excel Add-In in C# in VS2015. When I click a button, let's say <code>btnShowData</code>,  I use the text of a textbox <code>textBox1</code> and I send this text to a method. When I change the text in the textbox, when clicking <code>btnShowData</code>, it always take the default value of the <code>textBox1</code>. </p>
  
  <pre><code>private void btnShowData_Click(object sender, EventArgs e)
  {
        MessageBox.Show(this.textBox1.Text);
        GetAS400Data(textBox1.Text);
  } 
  </code></pre>
  
  <p><code>textBox1</code> is a TextBox in a WinForm I launch.</p>