rspec/rules/S1696/csharp/rule.adoc

``NullReferenceException`` should be avoided, not caught. Any situation in which ``NullReferenceException`` is explicitly caught can easily be converted to a ``null`` test, and any behavior being carried out in the catch block can easily be moved to the "is null" branch of the conditional.

== Noncompliant Code Example

----
public int GetLengthPlusTwo(string str) 
{
    int length = 2;
    try 
    {
       length += str.Length;
    }
    catch (NullReferenceException e) 
    {
        log.info("argument was null");
    }
    return length;
}
----

== Compliant Solution

----
public int GetLengthPlusTwo(string str) 
{
    int length = 2;

    if (str != null) 
    {
        length += str.Length;
    }
    else 
    {
        log.info("argument was null");
    }
    return length;
}
----

== See

* http://cwe.mitre.org/data/definitions/395.html[MITRE, CWE-395] - Use of NullPointerException Catch to Detect NULL Pointer Dereference
* https://wiki.sei.cmu.edu/confluence/x/_TdGBQ[CERT, ERR08-J.] - Do not catch NullPointerException or any of its ancestors