How to resolve "Input string was not in the correct format" error

Question

Greetings experts,

I have checked out some of the suggested solutions but none appears to help my problem.

I have a fieldname called caseNumber with Smallint data type in sql server database.

When I use the following line in my c# code:

if (caseNumber.Text != ""), I get the following error:

Input string was not in the correct format

I tried adding zero inside the quotes but same error.

Any ideas?

Many thanks in advance

Answer 1

That particular line of code will not generate the error you're talking about. It is a simple string comparison. I'm making an assumption here that caseNumber is a web control, maybe a Textbox? Can you confirm?

If it is a Textbox then that should just be retrieving the value as a string (everything is convertible to that) and then comparing it against an empty string. But what we cannot tell is if that control is actually something else (perhaps a third party library) or using something like the AJAX mask property or something. In those cases it is possible the property is trying to convert the actual value to a formatted value but that would seem odd since Text shouldn't be touched directly and is how the value would get back to the server anyway.

Can you please provide more context around that particular field in your code? Additionally please post the exception details including the inner exception (if any) and the stack trace.

Answer 2

Hi @Michael Taylor ,

Yes, it is correct that is a textbox.

The error points to that line.

Ok, we have a situation where you select user information and load that information on the screen.

The screen has a prepopulated caseNumber to be associated with this user.

However, when loading this particular user information to the screen, it comes blank. Not only does it not load the the screen, it erases the prepopulated caseNumber.

An attempt to reload this user information into the screen, produces the "Input not in the correct format" error just because the prepopulated caseNumber on the screen was erased.

FormtException; System,Number.StringToNumber...

Answer 3

Hi @Simflex ,

Input string was not in the correct format

Based on the information you have provided so far, your data type is Smallint and you need to convert the specified value to an integer.
https://learn.microsoft.com/en-us/dotnet/api/system.convert.toint16?view=net-6.0
E.g:

 int? Number = Convert.ToInt16(caseNumber.Text);  
            if (Number != null)  
            {  
  
            }  

If you can, I suggest you provide more detailed information, such as a small example that reproduces the problem.

Best regards,
Lan Huang

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