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POC# MVC Syntax - Recursive seeking in a template lambda (EditorFor)
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  1. POC# MVC Syntax - Recursive seeking in a template lambda (EditorFor)
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    copied!<p>I have a recursive model. </p> <pre><code>public class Mapping { public string Value { get; set; } public List&lt;Mapping&gt; ChildMappings { get; set; } } </code></pre> <p>I have an EditorTemplate for the Mapping class. Normal rendering via EditorFor( m => m.ChildMappings) works fine.</p> <p>Based on an array parameter (2,3), I'd like to seek a specific descendant node. (Mapping.ChildMappings[2].ChildMappings[3] for example).</p> <p>I've tried calling a local method within the lambda, which gave me an error about indexers and all the things I can't do in a template.</p> <pre><code>@Html.EditorFor(m =&gt; RecurseMappings(m.BodyMappings, indexes)) @functions{ private Mapping RecurseMappings(List&lt;Mapping&gt; mappings, int[] indexes) { Mapping mapping = new Mapping(); foreach (int index in indexes) { mapping = mappings[index]; if (mapping.ChildMappings == null) { mapping.ChildMappings = new List&lt;RequestMapping&gt;(); } mappings = mappings[index].ChildMappings; } return mappings[mappings.Count - 1]; } </code></pre> <p>For the moment I've fallen back on a switch to at least facilitate a hard coded number of nested levels, like this:</p> <pre><code> string[] tokens = Model.ChildIndex.Split(','); int[] indexes = Array.ConvertAll&lt;string, int&gt;(tokens, int.Parse); switch (indexes.GetLength(0)) { case 1: { var last = Model.BodyMappings[indexes[0]].ChildMappings.Count - 1; @Html.EditorFor(m =&gt; m.BodyMappings[indexes[0]].ChildMappings[last]) break; } case 2: { var last = Model.BodyMappings[indexes[0]].ChildMappings[indexes[1]].ChildMappings.Count - 1; @Html.EditorFor(m =&gt; m.BodyMappings[indexes[0]].ChildMappings[indexes[1]].ChildMappings[last]) break; } case 3: { var last = Model.BodyMappings[indexes[0]].ChildMappings[indexes[1]].ChildMappings[indexes[2]].ChildMappings.Count - 1; @Html.EditorFor(m =&gt; m.BodyMappings[indexes[0]].ChildMappings[indexes[1]].ChildMappings[indexes[2]].ChildMappings[last]) break; } case 4: { var last = Model.BodyMappings[indexes[0]].ChildMappings[indexes[1]].ChildMappings[indexes[2]].ChildMappings[indexes[3]].ChildMappings.Count - 1; @Html.EditorFor(m =&gt; m.BodyMappings[indexes[0]].ChildMappings[indexes[1]].ChildMappings[indexes[2]].ChildMappings[indexes[3]].ChildMappings[last]) break; } case 5: { var last = Model.BodyMappings[indexes[0]].ChildMappings[indexes[1]].ChildMappings[indexes[2]].ChildMappings[indexes[3]].ChildMappings[indexes[4]].ChildMappings.Count - 1; @Html.EditorFor(m =&gt; m.BodyMappings[indexes[0]].ChildMappings[indexes[1]].ChildMappings[indexes[2]].ChildMappings[indexes[3]].ChildMappings[indexes[4]].ChildMappings[last]) break; } default: break; } </code></pre> <p>So, Is there a way to wrap up what I have working in a package more like my failed first attempt? I've also tried a lambda code block, only to be denied because it can't be converted to an expression tree.</p>
 

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