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PODynamic Sort Criteria for Generic List
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  1. PODynamic Sort Criteria for Generic List
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    copied!<p>The purpose of this is to avoid writing a ton of if() statements.</p> <p>Here is my current code:</p> <pre><code>public override List&lt;oAccountSearchResults&gt; SearchForAccounts(oAccountSearchCriteria searchOptions) { List&lt;oAccountSearchResults&gt; results = Service.SearchForAccounts(searchOptions); results.Sort((a1, a2) =&gt; a2.AccountNumber.CompareTo(a1.AccountNumber)); return results; } </code></pre> <p>What I would like to do is provide a parameter which tells me which field to sort on. Then dynamically update my sort criteria without having a bunch of if() statements such as this:</p> <pre><code>public override List&lt;oAccountSearchResults&gt; SearchForAccounts(oAccountSearchCriteria searchOptions, string sortCriteria) { List&lt;oAccountSearchResults&gt; results = Service.SearchForAccounts(searchOptions); if (sortCriteria == "AccountNumber") { results.Sort((a1, a2) =&gt; a2.AccountNumber.CompareTo(a1.AccountNumber)); } else if (sortCriteria == "FirstName") { results.Sort((a1, a2) =&gt; a2.FirstName.CompareTo(a1.FirstName)); } return results; } </code></pre> <p>I would like to do this without having about 30 if() statements for all the sortable criteria that will be available. </p> <p>Any and all help will be appreciated.</p> <p><strong>EDIT WITH SOLUTION:</strong></p> <p>Thank you all for your responses.</p> <p>David, your approached worked but I think that Richard's answer works a bit better.</p> <p>Here is the ultimate solution that I came up with. I used David's framework for the example and Richards implementation:</p> <pre><code>using System; using System.Collections.Generic; namespace SortTest { class Program { static void Main(string[] args) { var results1 = Search(oObject =&gt; oObject.Value1); foreach (oObject o in results1) { Console.WriteLine(o.Value1 + ", " + o.Value2); } Console.WriteLine(Environment.NewLine); var results2 = Search(oObject =&gt; oObject.Value2); foreach (oObject o in results2) { Console.WriteLine(o.Value1 + ", " + o.Value2); } Console.ReadLine(); } public static List&lt;oObject&gt; Search&lt;T&gt;(Func&lt;oObject, T&gt; keyExtract) where T: IComparable { var results = new List&lt;oObject&gt; { new oObject {Value1 = "A 1", Value2 = "B 2"}, new oObject {Value1 = "B 1", Value2 = "A 2"} }; results.Sort((a, b) =&gt; keyExtract(a).CompareTo(keyExtract(b))); return results; } } class oObject { public string Value1 { get; set; } public string Value2 { get; set; } } } </code></pre>
 

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