title: Use object from MainForm in Class
body: <p>I'm writing a application in C# WPF.</p>
  
  <p>I am having a small issue here.</p>
  
  <p>In the class.cs, I have a line:</p>
  
  <pre><code>MessageBox.Show("Cancelled sending !");
  </code></pre>
  
  <p>And on my form I have a radioButton1.</p>
  
  <p>How can I make it like</p>
  
  <pre><code>if (radioButton1.IsChecked == true)
  {
      MessageBox.Show("Cancelled sending !");
  }
  </code></pre>
  
  <p>Because when I try it, it doesn't find the radioButton1</p>
  
  <p>I have tried it different ways, but I can't find how to do it.</p>