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    <p>EDIT: Complications with type-inference.</p> <p>Here's a way, the idea is to constrain the dictionary-values' type to be an<code>IEnumerable</code>of <em>something</em>.</p> <p>Unfortunately, type-inference doesn't seem to work with this signature (tested with C# 3), so you will have to specify the generic arguments explicitly.</p> <pre><code>public static IEnumerable&lt;TUnderlyingValue&gt; GetValueOrEmpty&lt;TKey, TUnderlyingValue, TValue&gt; (this IDictionary&lt;TKey, TValue&gt; source, TKey key) where TValue : IEnumerable&lt;TUnderlyingValue&gt; { if(source == null) throw new ArgumentNullException("source"); TValue retVal; return source.TryGetValue(key, out retVal) ? retVal : Enumerable.Empty&lt;TUnderlyingValue&gt;; } </code></pre> <p><strong>Usage</strong>:</p> <pre><code>var dict = new Dictionary&lt;string, int[]&gt; { { "foo", new[] { 6, 7, 8 } } { "bar", new[] { 1 } } }; var fooOrEmpty = dict.GetValueOrEmpty&lt;string, int, int[]&gt;("foo"); // { 6, 7, 8 } var barOrEmpty = dict.GetValueOrEmpty&lt;string, int, int[]&gt;("bar"); // { 1 } var bazOrEmpty = dict.GetValueOrEmpty&lt;string, int, int[]&gt;("baz"); // { } </code></pre> <p>Alternatively, we could use just 2 generic parameters without any constraints, but this will make the dictionary type less flexible. In this case, the compiler will infer the generic arguments just fine.</p> <pre><code>public static TUnderlyingValue[] GetValueOrEmpty&lt;TKey, TUnderlyingValue&gt; (this IDictionary&lt;TKey, TUnderlyingValue[]&gt; source, TKey key) { if(source == null) throw new ArgumentNullException("source"); TUnderlyingValue[] retVal; return source.TryGetValue(key, out retVal) ? retVal : new TUnderlyingValue[0]; } </code></pre>
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    1. POIenumerable Extension method for dictionary array calls
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    1. COThank you.... I eventually have combined some answers and have built this extension methods which seems to do the job, thank you for your input all including Winston as I used your idea too:
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    2. COpublic static IEnumerable<TValueType> TryGetValue<TValueType, Tkey, TValue>(this IDictionary<Tkey, TValue> source, Tkey ItemKey) { TValue foundList; if (source.TryGetValue(ItemKey, out foundList)) { return (IEnumerable<TValueType>) foundList; } return Enumerable.Empty<TValueType>(); }
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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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