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POHow to simplify complicated conditional clauses when using LINQ to SQL
 

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  1. POHow to simplify complicated conditional clauses when using LINQ to SQL
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    <p>Complicated statements with lots of AND/OR compenents are horrible to read and prone to errors - in a normal IF statement I might make use of a method call to simplify the is statement - for example:</p> <pre><code> if (((user == myUser || user == yourUser) &amp;&amp; user != Admin) &amp;&amp; Something &gt; SomethingElse &amp;&amp; (thresholdDate &gt; item.itemDate || (item.itemDate == null &amp;&amp; item.itemType == itemIsDated)) ) { DoStuff(); } </code></pre> <p>I could refactor out the user and date parts to make things easier to read:</p> <pre><code> if ( UserValid(user) &amp;&amp; Something &gt; SomethingElse &amp;&amp; DateIsValid(thresholdDate, item) ) { DoStuff(); } </code></pre> <p>What can I do in a LINQ query to simplifiy the nested IF?</p> <p>For example if I have something along the lines of:</p> <pre><code> var someResults = DataManager.Things .Where(item =&gt; (item.UserName == currentUser.UserName || item.ParentUsername == currentUser.UserName) &amp;&amp; (item.ItemType == (int) ItemType.MyType || item.ItemType == (int) ItemType.YourType) &amp;&amp; item.Result == null &amp;&amp; ( (item.Status == null &amp;&amp; (item.ItemDate &lt; thresholdDate || item.ItemType == (int) ItemType.YourType) ) || (item.Status != null &amp;&amp; item.Status != "Rejected") ) ) </code></pre> <p>** not actual code - just a simplified and generic example.</p> <p>I'd like to be able to extract parts of the logic into methods - or in some other way seperate out the AND / OR mess such that it's clear what is going on.</p> <p>I've tried adding a method to the 'item' to perfrom some of the logic a kind of IsValidType(typeOptions) method - this compiles fine but LINQ complains that it does't recognise the method at runtime.</p> <p>I could use a property on the item - but then I can't pass any context information (which makes it of limited use)</p> <p>How do you go about making this kind of query readable?</p>
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    1. USTyco Kaine
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      1. USSergey Berezovskiy
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    1. COIf it's Linq-To-Sql tag it accordingly because in Linq-To-Objects it's no problem to use methods.
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      1. USTim Schmelter
    2. CO@TimSchmelter - good point - amended
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