FormatException: Input string was not in a correct format.

Question

I am receiving the error "FormatException: Input string was not in a correct format."
when running my code.

The issue is coming from the following lines:

int companyId = User.Identity.GetCompanyId().Value;  
  
public static int? GetCompanyId(this IIdentity identity)  
        {  
            Claim claim = ((ClaimsIdentity)identity).FindFirst("CompanyId");  
            
            return (claim != null) ? int.Parse(claim.Value) : null;  
        }  

In breakpoint mode, when the arrow hits line 7 above,
the value of claim (claim.value) is "" which is as good as null, or an empty string if I am right.

So I expect the method to return null.

After looking at similar instances of this error, there always appears to be issues in the parsing.
So I suspect I need to change the parsing type, but without further help from the error message I am taking a guess.

Can someone please tell me what is wrong here? Thank you.

Answer 1

Hi @lm1212 ,

It is impossible to convert empty string/null value to int type by using int.Parse(claim. Value) which is the reason why you get such error.

You need change your code like below:

 return (claim != null & !string.IsNullOrEmpty(claim?.Value)) ? int.Parse(claim.Value) : null;  

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Best Regards,
Rena