title: How to format floating point value with fix number of digits?
body: <p>Is it possible in C# to format a double value with double.ToString in a way that I have always a fixed number of digits, no matter on which side of the decimal point?</p>
  
  <p>Say I wish 6 digits, I want to have these results:</p>
  
  <ul>
  <li>0.00123456789 gives "0.00123"</li>
  <li>1.23456789 gives "1.23457"</li>
  <li>123.456789 gives "123.457"</li>
  <li>0.0000000123456789 gives "0.00000"</li>
  <li>12345678.9 gives "12345679" (on overflow I want to see all digits left of decimalpoint)</li>
  <li>4.2 gives "4.20000"</li>
  </ul>
  
  <p>I'm experimenting with double.ToString, but cannot find any suitable format string.</p>
  
  <p>Already tried "G6" (gives sometimes exponential format), "F6" (comes close, but 0.123456789 gives "0.123457" which are 7 digits).</p>