Here is a piece of code:
IUser user = managerUser.GetUserById(UserId);
if ( user==null )
throw new Exception(...);
Quote quote = new Quote(user.FullName, user.Email);
Everything is fine here. But if I replace "if" line with the following one:
ComponentException<MyUserManagerException>.FailIfTrue(user == null, "Can't find user with Id=" + UserId);
where function implementation is following:
public abstract class ComponentException<T> : ComponentException
where T : ComponentException, new()
{
public static void FailIfTrue(bool expression, string message)
{
if (expression)
{
T t = new T();
t.SetErrorMessage(message);
throw t;
}
}
//...
}
Then ReSharper generates me a warning: Possible 'System.NullReferenceException' pointing on 1st usage of 'user' object.
Q1. Why it generates such exception? As far as I see if user==null
then exception will be generated and execution will never reach the usage point.
Q2. How to remove that warning? Please note:
1. I don't want to suppress this warning with comments (I will have a lot of similar pieces and don't want to transform my source code in 'commented garbage);
2. I don't want to changes ReSharper settings to change this problem from warning to 'suggestion' of 'hint'.
Thanks.
Any thoughts are welcome!
P.S. I am using resharper 5.1, MVSV 2008, C#
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