title: Hanging of C# WinForm Application when updating richtextbox with processing steps
body: <p>through every step of my very long-code scheduling processing, I write down the result to a richTextBox, with lines that might exceeds thousands of lines,  the application falls in the "not responding status", i discovered this problem by chance just when i disable this step. But, i still need a way to get a complete description of my app processing history, do you have any alternative suggestions</p>
  
  <p>my code seems like that:</p>
  
  <pre><code>public void mycode()
  {
  //code part one
  richTextBox1.text += "result is: abc";
  
  //code part two
  richTextBox1.text += "result is: efg";
  
  //code part three
  richTextBox1.text += "result is: hij";
  
  }
  </code></pre>