如何保持两位数精度

Question

I'm struggling to find a better way to preserve the 2 digit precision for decimal variable.

Here I have divided the question in 2 steps:

Step1: SQL Query

Inorder to get a 2 digit precision in a SQL query, I'm using

CONVERT(DECIMAL(10,2), .....) // to get 2 digit precision

On execution, I'm able to achieve the 2 digit precision in my SSMS.

NET_TOTAL  
---------    
10.00  
12.50  
14.25

Step2: via C# code

Whereas in my C# code, when I tried to store the value in my C# code it is not preserving the 2 digit precision.

NET_TOTAL  
---------    
10       //lost my precision
12.5     //lost my precision
14.25

Following is my variable declaration.

public decimal? NET_TOTAL { get; set; } 

But I can smell a workaround using properties, but I'm not able to get it.

I'm using

• dapper.net for database operations.
• FileHelper.dll for converting the query list to a CSV file.

I would like to know the reason and a way to solve this problem.

Any help is much appreciated.

Thanks in advance.

Answer 1

Trailing zeros to the right of the decimal is not precision.
It is just presentation.

decimal d;
d = 10;
System.Diagnostics.Debug.WriteLine(string.Format("{0:N2}",d));

Answer 2

You can use

decimal.Round(value,decimalPoints);

This will return a decimal rounded upto decimalPoints.

Answer 3

You are confusing precision with representation. What you see in SSMS is a formatted number (a string). What you have in C# (and inside the DB) is a "true" number. In a true normally ending 0 after the decimal point aren't included.

If you want to format it you can do something like NET_TOTAL.ToString("0.00")

Note that there could be another problem:

NET_TOTAL = 1.245;

decimal sum = NET_TOTAL + NET_TOTAL;

the sum will be 2.29, but after a roundtrip to the DB NET_TOTAL will be 1.24 or 1.25 (depending on how the DB rounded 1.245) and the recalculated sum will be 2.28 or 2.3 .

Answer 4

is this acceptable:

  private decimal? _netTotal; public decimal? NET_TOTAL{ get{ return _netTotal; } set { if (value.HasValue) { _netTotal = Math.Truncate(value.Value, 2); // or rounding }else{ _netTotal = value; } } } 

if you want to keep the original value but present it with 2 decimal places, then you could modify the getter instead: return Math.Truncate(value.Value, 2);