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POLambda expression oddity
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copied!<p>Long story short. I have 2 lists which contain the same type (but are used for different things) and I want to know if EITHER list contains an item with a certain name.</p> <p>My original code, which worked prefectly, was:</p> <pre><code>if (listA.Any(var => var.Name == strMatch) || listB.Any(var => var.Name == strMatch)) { //Do something } </code></pre> <p>This code worked perfectly, whether the item was present in either or both lists. Later on, I had several 'impossible' crashes -- Things which never could have happened. I traced it back to that if statement NEVER returning true.</p> <p>This stumped me for ages... I couldn't work out what was going wrong. Eventually I gave up and stuck brackets around the body of the lamda expressions like so...</p> <pre><code>if (listA.Any(var => (var.Name == strMatch)) || listB.Any(var => (var.Name == strMatch))) { //Do something } </code></pre> <p>After re-running my program, all the 'impossible' errors went away and it functioned normally. Removing the extra backets cause the errors to reappear.</p> <p>I've never had this problem with lambda expressions before (especially where they work and THEN, after several runs working correctly break) and my other lambda expressions work correctly.</p> <p>Example: The following code works 100% as expected (Assuming that there is a match in one of the lists)</p> <pre><code>Item item = ListA.FirstOrDefault(var => var.Name == strMatch) ?? ListB.FirstOrDefault(var => var.Name == strMatch); </code></pre> <p>What's going on? Why is the compiler picky about <strong>some</strong> lamda expressions and not others? (Even when they are identical?) ???</p> <p><strong>UPDATE :: System Details</strong> This was encountered with Microsoft Visual Studio 2008 (Professional), Windows Vista 32bit.</p> <p><strong>UPDATE</strong> <a href="http://www.youtube.com/watch?v=VVROKeNGa-g" rel="nofollow">Video link</a>, this has been test on other computers and is <strong>NOT</strong> reproducable. Makes me feel like my computer is doomed. Reinstallion of VS has no effect.</p> <p>Please ignore any background cat noises, she only meows alot when she hears me recording something.</p>

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