title: Adding textbox values
body: <p>In Asp.net using c# ,I am having</p>
  
  <pre><code>int sum = Convert.ToInt32(txtbox1.Text) + Convert.ToInt32(txtbox2.Text);
  </code></pre>
  
  <p>When i have an empty textbox, i get the error "Input string is not in a correct format".</p>
  
  <p>So, I am wondering if there is a simple way to add textbox values only they are integers, if not  take the textbox value as 0. </p>
  
  <p>Thanks in advance!</p>