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POOrderByWithDirection when direction depends on data
 

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    <p>In this SO article: <a href="https://stackoverflow.com/questions/388708/ascending-descending-in-linq-can-one-change-the-order-via-parameter">ascending/descending in LINQ - can one change the order via parameter?</a> a solution was presented for how to conditionally order in ascending or descending order.</p> <p>what the article doesn't cover is, what if I want to make the decision based on the data in the query (which is, actually, what is most likely)?</p> <p>I cannot seem to do:</p> <pre><code>source.OrderByWithDirection(o =&gt; o.MyColumnToOrderBy, o =&gt; o.SortingDirection) </code></pre> <p>would I then need to rewrite the methods? how?</p> <p><strong>- update -</strong></p> <p>by way of rationale, here is what I'm looking to accomplish:</p> <pre><code>Strike Type Price 98 Ask 101 98 Ask 100 98 Ask 99 98 Bid 95 98 Bid 96 98 Bid 97 </code></pre> <p>as you can see, asks are sorted down but bids are sorted up such that the rows with the greatest difference are next to each other. so what I'd like to say is something like:</p> <pre><code>source.OrderBy(o =&gt; new { o.Strike, o.Type }) .ThenByWithDirection(o =&gt; o.Price, o =&gt; o.Type == "Ask" ? __down__ : __up__) </code></pre> <p><strong>- update II -</strong></p> <p>a clumsy way to do this would be to issue two separate queries like this:</p> <pre><code>source .Where(o =&gt; o.Type == "Ask") .OrderBy(o =&gt; new { o.Strike, o.Type }) .ThenBy(o =&gt; o.Price) source .Where(o =&gt; o.Type == "Bid") .OrderBy(o =&gt; new { o.Strike, o.Type }) .ThenByDescending(o =&gt; o.Price) </code></pre> <p>and concatenate them</p>
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    1. CO`o` is an member of the IEnumerable? What if different elements had different values for SortingDirection? Or am I misunderstanding?
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      1. USbmm6o
    2. CO@bmm6o, `o` represent a record within the query. different records will have different values for `o.SortingDirection`, which is the point of my question
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    3. COFor what it's worth, while it may be "most likely" to you, it's not something I've ever heard requested before - whereas the ability to simply have a programmatic ascending/descending, usually based on user input to the query (rather than the data within the question) is a fairly common request.
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      1. USJon Skeet
 

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