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POSpliting up long linq queries for improved maintainability
 

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  1. POSpliting up long linq queries for improved maintainability
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    <p>I have a bunch of these Tasks that are all based on LINQ queries. I am looking for good way to refactor them and make them easier to read and allow me to change the queries depending on language/region etc.</p> <pre><code>var mailTaskOne = CreateTask(() =&gt; myService.Mail.Where(p =&gt; p.ProjectName == "Delta" &amp;&amp; (p.MailLang== (int)MailLanguage.EU || p.MailLang == (int)MailLanguage.RU) &amp;&amp; (p.DateEntered &gt;= startDate &amp;&amp; p.DateEntered &lt;= endDate) &amp;&amp; p.MailPriority == (int)MailPriority.High).Count()); </code></pre> <p>One of the ways I thought would be convenient would be to split the query up into something like this.</p> <pre><code>var results = myService.Mail.Where(x =&gt; x.ProjectName == "Delta"); results = results.Where(p =&gt; p.MailLang== (int)MailLanguage.EU); results = results.Where(p =&gt; p.DateModified &gt;= startDate &amp;&amp; p.DateModified &lt;= endDate); </code></pre> <p>This would allow me to do this without having to repeat the whole query for each region.</p> <pre><code>if (MailLanguage == "English") results = results.Where(p =&gt; p.MailLang== (int)MailLanguage.EU); else results = results.Where(p =&gt; p.MailLang== (int)MailLanguage.RU); </code></pre> <p>Is there anyone that knows a better solution for this? I end up having huge functions as I need to do maybe 20 of these queries depending on the requirements; such as Region, Project name etc.</p> <hr> <p><strong>Edit:</strong></p> <p>Due to some limitations I did not know of with the back-end (web service/api) I could unfortunately not use some of the awesome answers mentioned in this question.</p> <p>For example this does not get translated properly, but in no ways because the answer incorrect, simply does not work with the API I am working against -- possibly because it is poorly implemented. </p> <pre><code>public bool IsValid(Type x) { return (x.a == b) &amp;&amp; (x.c ==d) &amp;&amp; (x.d == e); } </code></pre> <p>Anyway, anyone looking for similar solutions all of these are valid answers, but in the end I ended up going with something similar to the solution snurre provided.</p>
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      1. USDavid Hall
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    1. COWhy don't you use language as a parameter/variable?
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      1. USFedor Hajdu
    2. COFeel free to explain further - my mind is at a blank at the moment. Keep in mind that there might be multiple languages, as for example English might for example be US + EU. :]
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    3. COAre you querying on database or memory?
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      1. USManar Husrieh
 

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