Converting Doubles to Strings

[nvx]

Hi,
I'm looking for a simple way to convert a Double to a String exactly
the .ToString() does, except these two differences:
- the number of decimals is given (rounding is applied if
necessary), and
- trailing zeroes are kept.

This means I need it to be converted using the scientific notation if
the number is greater than a certain value etc., not just a simple
"this number of digits (or more if needed) before the decimal point
and precisely this number of decimals after the decimal point."

I could round the Double before converting it to a String
using .ToString(), but the trailing zeroes would be omitted.
Similarly, I could use the format string "0.00" or "0.00E+00", but the
scientific notation would not or would be used respectively (i.e.
converting 100.567 to "100.57" (which is OK) / "1.00E+02" (which means
a significant loss of data) and converting 123456789123456 789.12345 to
"12345678912345 6789.12" (awful...) / 1.23E+15 (this is the correct
conversion now)).

So, do I need to create an appropriate format string according to the
current Double value or is there some elegant solution of this?

Thanks for any help...

With regards
nvx

[Jeff T]

You could make a separate function that takes in the double and
returns the string using your logic for if it is greater than a
certain value use the scientific notation if not use the other
formatting.

Or you could create a new class that inherits from double and
overrides the ToString method. This might be overkill though
depending on your exact situation.

[Larry Lard]

Jeff T wrote:

You could make a separate function that takes in the double and
returns the string using your logic for if it is greater than a
certain value use the scientific notation if not use the other
formatting.

Or you could create a new class that inherits from double and
overrides the ToString method. This might be overkill though
depending on your exact situation.

Overkill and/or impossible (double is a struct; structs are inherently
sealed).

--
Larry Lard
la*******@googl email.com
The address is real, but unread - please reply to the group
For VB and C# questions - tell us which version

[nvx]

Thanks both of you for your replies. It seems I'll have to code a bit
more...

With regards
nvx
Larry Lard napsal:

Jeff T wrote:

You could make a separate function that takes in the double and
returns the string using your logic for if it is greater than a
certain value use the scientific notation if not use the other
formatting.

Or you could create a new class that inherits from double and
overrides the ToString method. This might be overkill though
depending on your exact situation.

Overkill and/or impossible (double is a struct; structs are inherently
sealed).

--
Larry Lard
la*******@googl email.com
The address is real, but unread - please reply to the group
For VB and C# questions - tell us which version