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POAutomapper and lazy loading with EF and performance
 

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    <p>I have a model like this</p> <pre><code>public class Exam { public int NewsId { get; set; } public string Title { get; set; } public string Description{ get; set; } public string Program{ get; set; } } </code></pre> <p>and a view model like this</p> <pre><code>public class ExamViewModel { public int NewsId { get; set; } public string Title { get; set; } } </code></pre> <p>and I do config Automapper like this</p> <pre><code>AutoMapper.Mapper.CreateMap&lt;Exam, ExamViewModel&gt;(); </code></pre> <p>and in an ActionResult I used Automapper like this:</p> <pre><code> public ActionResult Exam() { var examsDb = db.Exams; IEnumerable&lt;ExamViewModel&gt; examViewModel = AutoMapper.Mapper.Map&lt;IEnumerable&lt;Exam&gt;, IEnumerable&lt;ExamViewModel&gt;&gt;(examsDb); return View(examViewModel); } </code></pre> <p>and in view I loop through it</p> <pre><code> @model IEnumerable&lt;AraParsESOL.ViewModels.ExamViewModel&gt; &lt;ul&gt; @foreach (var e in Model) { &lt;li&gt; @Html.ActionLink(e.Title, "Type", "Exam") &lt;/li&gt; } &lt;/ul&gt; </code></pre> <p>My problem is that: As you can see in the Model There are 4 properties but in viewModel there are only 2 properties.</p> <p>How can i get only those 2 properties in viewModel and not the entire Model?</p> <p>What happens here is that in view after each loop it goes and get the required column from the database but i want only those 2 properties and not going back to database.</p> <p>i can get the database like this db.Exam.ToList(); but it will cause the entire database gets back. i want to use best practices here?</p> <p>i know i can get the data from database by anonymouse type and select command but then what is the use of automapper? what is the best solution here?</p>
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    1. US1AmirJalali
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    1. COWhat do you mean by *each loop it goes and get the required column from the database but i want only those 2 properties and not going back to database*? You have no lazy loading in your model - lazy loading affect only related entities but your model doesn't have any. Also your code should perform the same as calling `db.Exam.ToList()`.
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      1. USLadislav Mrnka
    2. COI mean in View after each loop, the database gets hit and required data get back. For each Row a select command goes to database and select those tow properties instead of just going once to the database and select all the rows and bringing back those required data.
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