RethrowException.qhelp

<!DOCTYPE qhelp SYSTEM "qhelp.dtd">
<qhelp>
<overview>
<p>
Rethrowing an exception variable will lose the stack trace in the original exception, and 
replace it with the stack trace from the <code>throw</code> statement.
This will make debugging the root cause of the exception more difficult, for example
if the stack trace is written to a log file.
</p> 

</overview>
<recommendation>
<p>
Consider using <code>throw;</code> to rethrow the original exception. Not only is this simpler, 
but it will retain the original stack information.
</p>

</recommendation>
<example>
<p>This example shows an exception handler which sets the status to <code>UnexpectedException</code>
if an exception is thrown. However it throws <code>ex</code> which discards the original
stack trace containing the source of the error.
</p>

<sample src="RethrowException.cs" />

<p>The fix is to replace the <code>throw</code> statement as follows:</p>
<sample src="RethrowExceptionFix.cs" />

<p>Since the variable <code>ex</code> is no longer needed, the catch variable has been removed.</p>

</example>
<references>

	<li>MSDN: <a href="https://msdn.microsoft.com/en-us/library/ms173163.aspx">Creating and Throwing Exceptions (C# Programming Guide)</a>.</li>
	<li>MSDN: <a href="https://msdn.microsoft.com/en-us/library/1ah5wsex.aspx">throw (C# Reference)</a>.</li>

</references>
</qhelp>