Issue when converting string to long in c#

Question

I want to convert string to Long. But I got this error:

Input string was not in a correct format

How to convert string to long in C#?

I follow this answer How could I convert data from string to long in c#

This is my code:

if (Convert.ToInt64("140.82") >= minPrice && 
    Convert.ToInt64(217.76) <= maxPrice) 
{
    // do filter
}  // on this line the exception is thrown

What is the mistake I made?

Be advised that the top voted answer on that question is actually wrong, and will give you that error. — Etienne de Martel, Dec 13 '21 at 02:37
Since you are typing the values into the code why not enter them as decimal rather than string (and something else in the case of `217.76`)? — Ňɏssa Pøngjǣrdenlarp, Dec 13 '21 at 02:41

score 1 · Answer 1 · edited Dec 13 '21 at 04:38

1

You cannot convert "140.82" to long value in C#. You can convert "140.82" to double and then convert to long.

(long)double.Parse("140.82")

edited Dec 13 '21 at 04:38

ZygD

22,092
39
79
102

answered Dec 13 '21 at 03:16

kiamehr hossin

64
4

Ryan Thom · Answer 2 · 2021-12-13T03:42:04.153

0

You are converting the string to an integer, not a long. The Convert.ToInt64() function cannot convert the decimal of the string into an int, as that would require truncating. Instead try Double.TryParse(), and then convert that to an integer. To remove the decimal so you can convert it to an int after converting it to a double, use either Math.Floor(), Math.Ceiling(), Math.Round(), or Math.Truncate().

edited Dec 13 '21 at 03:42

answered Dec 13 '21 at 02:24

Ryan Thom

25
9

1

Well, a long is an integer, but yes, the issue is the decimal value. – Etienne de Martel Dec 13 '21 at 02:32

score 0 · Answer 3 · answered Dec 13 '21 at 04:51

If you are going to use the Convert.ToInt64(param) method to convert string data to long, it is expected that the current data format should conform to the target data format. If the Convert.ToInt64() method is to be used, the string data must be in long format.

int minPrice = 100;

if(minPrice <= Convert.ToInt64("140"))
{
    Console.WriteLine("Value: {0}", Convert.ToInt64("140"));
}

The other method is to use the Convert.ToDouble() method if you are sure the string is in floating point format:

int minPrice = 100;

if(minPrice <= (long)Convert.ToDouble("140.82"))
{
    Console.WriteLine("Value: {0}", Convert.ToDouble("140.82"));
}

Issue when converting string to long in c#

3 Answers3