Question

Yesterday I asked this general question about decimals and their internal precisions. Here is a specific question about the scenario I’m trying to address.

I have column in SqlServer that is typed – decimal(18,6).
When I fetch these values, the .net decimals that are created match the precision in the database. They look like this:

1.100000
0.960000
0.939000
0.844400
0.912340

I need to present (ToString) these values according to these rules:

• Non-zeroes are always shown.
• Trailing zeroes on or before the nth decimal place are shown.
• Trailing zeroes after the nth decimal place are not shown.

So, this is what I want when n is 3:

1.100
0.960
0.939
0.8444
0.91234

Now, I have written some code that ToString’s the decimal – removing all trailing zeroes, and then analyzes the string looking for a decimal point and counts the number of decimal places to see how many trailing zeroes need to be added back on. Is there a better way to accomplish this?

Also, I know I said ToString in the question above… but if I could modify the decimals on their way out of my data-access layer, such that consumers always get decimals with the proper precision, that would be better. Is it possible to perform this operation on the decimal itself without string manipulation?

Answer 1

To output your required format with n=3, you could use:

number.ToString("0.000###")

With n as a parameter, then you could build a custom string format:

string format = "0." + new string('0', n) + new string('#', 6 - n);
s = number.ToString(format);