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    <p>It is not directly possible to filter on the first item of a collection relation (such as <code>Bs[0]</code>), for one because <code>ICollection&lt;B&gt;</code> does not have an indexer.</p> <p>However, it is possible to use predicates such as <code>Any</code> in a Dynamic Linq expression, such as:</p> <pre><code>result = list.Where("Bs.Any(Id = @0)", value); </code></pre> <p>which is equivalent to</p> <pre><code>result = from a in list where a.Bs.Any(b =&gt; b.Id == value) select a; </code></pre> <p>(This translates to an <code>EXISTS</code> query in SQL.)</p> <p>I think that's what you're after, not <code>Bs[0]</code>.</p> <hr> <p>The full list of supported predicates and aggregates for System.Linq.Dynamic seems to be: </p> <ul> <li><strong>Where</strong>(<em>condition</em>)</li> <li><strong>Any</strong>() and <strong>Any</strong>(<em>condition</em>)</li> <li><strong>All</strong>(<em>condition</em>)</li> <li><strong>Count</strong>() and <strong>Count</strong>(<em>condition</em>)</li> <li><strong>Max</strong>(<em>selector</em>)</li> <li><strong>Min</strong>(<em>selector</em>)</li> <li><strong>Sum</strong>(<em>selector</em>)</li> <li><strong>Average</strong>(<em>selector</em>)</li> </ul> <p>For <code>Bs[0].Id = @0</code> you'd need to have support for <strong>First</strong>(<em>condition</em>), which you could add to a private copy of System.Linq.Dynamic, by editing the interface <code>IEnumerableSignatures</code>, adding</p> <pre><code>void First(); void First(bool predicate); void FirstOrDefault(); void FirstOrDefault(bool predicate); </code></pre> <p>(Adding Last(OrDefault) and Single(OrDefault) as well would be a logical step IMHO.)</p>
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Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

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