title: Do calculation on text formatted as single number format in C#
body: <p>I understand how to format some number text into a number format using string.format function like this:</p>
  
  <pre><code>TextBox1.Text = String.Format("{0:n}", "5000.52");
  
  // Outputs: 5,000.52
  </code></pre>
  
  <p>but the real issue for me is when using this formatted text again in some calculation like this:</p>
  
  <pre><code>Single y = Single.Parse(TextBox1.Text) * 123;
  </code></pre>
  
  <p>C# compiler complains and says:</p>
  
  <p><code>System.FormatException: 'Input string was not in a correct format.'</code></p>
  
  <p>So, I need to know what is the professional way to overcome this issue as I really concerned about my application performance.</p>