How To Mix Decimal Places

Using Visual Studio I'm using TextRange processing a word at a time, parsing for figures and minus values etc. All of which works. However I have to honour the original number of decimal places in the figures, even though they may be 0's.ie -1219.0 and 1219.00 are both valid inputs the valid outputs would be(1,219.0) and 1,219.00, I can't just use tostring and stamp all of them as "N2" etc).I have to format including retaining the trailing 0 if necessary.I can use "#,##0.######" but that removes trailing 0's... ie both above example would be changed to 1,219 pos or neg.