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POWhy does this (null || !TryParse) conditional result in "use of unassigned local variable"?
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  1. POWhy does this (null || !TryParse) conditional result in "use of unassigned local variable"?
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    copied!<p>The following code results in <em>use of unassigned local variable "numberOfGroups"</em>:</p> <pre><code>int numberOfGroups; if(options.NumberOfGroups == null || !int.TryParse(options.NumberOfGroups, out numberOfGroups)) { numberOfGroups = 10; } </code></pre> <p>However, this code works fine (though, <a href="http://en.wikipedia.org/wiki/ReSharper" rel="noreferrer">ReSharper</a> says the <code>= 10</code> is redundant):</p> <pre><code>int numberOfGroups = 10; if(options.NumberOfGroups == null || !int.TryParse(options.NumberOfGroups, out numberOfGroups)) { numberOfGroups = 10; } </code></pre> <p>Am I missing something, or is the compiler not liking my <code>||</code>?</p> <p>I've narrowed this down to <code>dynamic</code> causing the issues (<code>options</code> was a dynamic variable in my above code). The question still remains, <strong>why can't I do this</strong>?</p> <p>This code <em>doesn't</em> compile:</p> <pre><code>internal class Program { #region Static Methods private static void Main(string[] args) { dynamic myString = args[0]; int myInt; if(myString == null || !int.TryParse(myString, out myInt)) { myInt = 10; } Console.WriteLine(myInt); } #endregion } </code></pre> <p>However, this code <em>does</em>:</p> <pre><code>internal class Program { #region Static Methods private static void Main(string[] args) { var myString = args[0]; // var would be string int myInt; if(myString == null || !int.TryParse(myString, out myInt)) { myInt = 10; } Console.WriteLine(myInt); } #endregion } </code></pre> <p>I didn't realize <code>dynamic</code> would be a factor in this.</p>
 

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