title: Access object from another class
body: <p>I'm trying to change the interval value of a timer (in Form1) from my settings form.
  I'm declaring the form1 with <code>static Form1 formInstance;</code>
  But it throws null exception on forminstance when i change the value. 
  I've also tried <code>Form1 form1 = new Form1();</code> but the application crashes when i open settings form. Note that i've already have timer modifier set to public.</p>
  
  <pre><code>public partial class SettingsForm : Form
  {
      static Form1 formInstance;
  </code></pre>
  
  <p>...</p>
  
  <pre><code>        if (Properties.Settings.Default.sync != Convert.ToInt32(textBox1.Text))
          {
              formInstance.timer1.Stop();
              formInstance.timer1.Interval = 60000;
              formInstance.timer1.Start();
          }
  </code></pre>