how to store null values in integer variable in C#

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I couldn't store null value to an integer variable using these codes ....

C#

int? i = Convert.ToInt32(orderqty.Text);
            int? counts = !string.IsNullOrEmpty(orderqty.Text) ? i : (int?)null;

            int? i1 = Convert.ToInt32(yarncounts.Text);
            int? counts1 = !string.IsNullOrEmpty(yarncounts.Text) ? i1 :(int?)null;

Is there any best methods to store null values to counts1 variable ??

Posted 29-Apr-14 0:51am

Sriram Ramachandran

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3 solutions

Solution 3

It isn't necessary to cast the null to (int?).
Also, using int.TryParse would catch other invalid input:

C#

int? counts1 = null;
int i1;
if (int.TryParse(yarncounts.Text, out i1))
{
  counts1 = i1;
}
else
{
  // here you can perform any additional error handling/reporting (but you don't HAVE to!)
}

Posted 29-Apr-14 7:13am

Matt T Heffron

Comments

phil.o 29-Apr-14 13:22pm

Quote: 'It isn't necessary to cast the null to (int?).'
I'm pretty sure it is :) Due to the "() ? :" construction : the compiler expects both arguments around the colon to be of the same unambiguous type.
Anyway voted 5 as your solution is as valid as both others :)

Matt T Heffron 29-Apr-14 13:32pm

Yes, I wasn't thinking in the context of the ?:

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OriginalGriff · Accepted Answer · 2014-04-29T01:00:00

Solution 1

Why?
That is some odd code: you do a conversion to integer - which will fail is the string is empty - then test to see if it's null or empty...
Check first, then convert:

C#

int? counts1 = string.IsNullOrEmpty(yarncounts.Text) ? (int?)null : int.Parse(yarncounts.Text);

Posted 29-Apr-14 1:00am

OriginalGriff

Raul Iloc · Accepted Answer · 2014-04-29T01:01:00

Solution 2

You should optimize the code like this:
int? counts1 = (string.IsNullOrEmpty(yarncounts.Text) ? (int?)null : Convert.ToInt32(yarncounts.Text);

Posted 29-Apr-14 1:01am

Raul Iloc