In .NET (C#) decimal is a 128 bit numeric data type. The type itself, like with all the other types not defines how much significant digits you may or may not have after the decimal point...
First you must understand that here is no numerical (mathematical) difference between 999 and 999.00, so there should not be any problem receiving one or the another...However if you talking about a formatting for display purposes, than you should format the output...
value.ToString("F2");
Where F means, fixed point, and 2 is the number of digits after the decimal point...
http://msdn.microsoft.com/en-us/library/dwhawy9k(v=vs.110).aspx[
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