title: c# ToString a decimal and force + sign AND number decimal places
body: <p>How can I do two things in tostring format:</p>
  
  <pre><code>1. Display number to x decimal places
  2. Also force a + sign so that negative an positive numbers lineup in nice columns.
  
  string fmt = "+N" + dp + ";-N" + dp;
  Console.WrtieLine(Open.ToString(fmt))
  </code></pre>
  
  <p>Does not work?</p>