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My code won't compile due to the error below:

The call is ambiguous between the following methods or properties: 'System.Math.Round(double, int)' and 'System.Math.Round(decimal, int)

My code is

Math.Round(new FileInfo(strFilePath).Length / 1024, 1)

How can I fix this?

Thanks

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3 Answers 3

Reset to default
53 
Math.Round(new FileInfo(strFilePath).Length / 1024d, 1)
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2
  • 6
    This is way better than the accepted answer, you should not implicitly cast using ".0", using 'd' suffix is explicit and preferred.
    – user275587
    Commented Jun 9, 2010 at 8:54
  • 3
    Better yes, but the explanation in the accepted answer as to why is extremely helpful.
    – jmgardn2
    Commented Oct 9, 2015 at 18:57
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The problem is that you make an integer division (results also in an int) and a int can be implicitly converted to both double and decimal. Therefore, you need to make sure the expression results in one of those; double is probably what you want.

Math.Round(new FileInfo(strFilePath).Length / 1024.0, 1)
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14 
Math.Round((double) (new FileInfo(strFilePath).Length / 1024), 1)
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3
  • why is this a negative 1? Please explain yourself negative rater so we understand why you did this. Seems logical to me to just cast it like he did.
    – PositiveGuy
    Commented Aug 18, 2011 at 15:54
  • I disagree with down vote since the answer is correct if you oversee the easy-to-make mistake. But you did need to put the new FileInfo(strFilePath).Length / 1024 in parenthesis to make it work.
    – Sellorio
    Commented May 26, 2013 at 23:08
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    The problem is that the divisions will still be integer division which will truncate, so rounding is pointless even if you cast to a double.
    – juharr
    Commented Feb 8, 2016 at 19:48