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POHow do you create a dynamic select projection from a generic using Linq in C#?
 

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  1. POHow do you create a dynamic select projection from a generic using Linq in C#?
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    <p>So I have a function that I pass Func call back to. I would also like to add some sort of selection projection to be able to do the projection on the object, meaning I would only perform one database call. The function looks something like this:</p> <pre><code>public T Get&lt;T&gt;(string id, Func&lt;T&gt; getItemCallback) where T : class { item = getItemCallback(); if (item != null) { doSomeThing(item); // Here I would like to call something else that is // expecting a specific type. Is there way to pass in a // dynamic selector? doSomethingElse(item.Select(x =&gt; new CustomType { id = x.id, name = x.name }).ToList()); } return item; } void doSomethingElse(List&lt;CustomType&gt; custom) { .... } </code></pre> <p>Leme show how I cam currently calling this perhaps that will help:</p> <pre><code>public List&lt;MyDataSet&gt; GetData(string keywords, string id) { return _myObject.Get( id, () =&gt; db.GetDataSet(keywords, id).ToList()); // Perhaps I could add another parameter here to // handled the projection ???? } </code></pre> <p>Thanks to Reed I figured it out...would look like this:</p> <pre><code>public T Get&lt;T&gt;(string id, Func&lt;T&gt; getItemCallback, Func&lt;T, List&lt;CustomType&gt;&gt; selector) where T : class { item = getItemCallback(); if (item != null) { doSomething(item); var custom = selector(item); if (custom != null) { doSomethingElse(custom); } } return item; } </code></pre> <p>And The call looks like:</p> <pre><code> public List&lt;MyDataSet&gt; GetData(string keywords, string id) { return _myObject.Get( id, () =&gt; db.GetDataSet(keywords, id).ToList(), x =&gt; x.Select(d =&gt; new CustomType { id = d.ReferenceId, name = d.Name }) .ToList()); } </code></pre>
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    1. USewahner
    1. USewahner
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    1. COIt's not clear what exactly your problem is. Please try to be clearer.
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      1. POHow do you create a dynamic select projection from a generic using Linq in C#?
      1. USDaniel Hilgarth
    2. COIt seems odd that you're getting a single item, but then doing "something else" on a `List<T>` of some other type...
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      1. POHow do you create a dynamic select projection from a generic using Linq in C#?
      1. USReed Copsey
    3. COWell the doSomething function expects just an object and it either logs it or caches it. The doSomethingElse expects a list of items that I would define in the calling function not in the Get<T> function.
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      1. POHow do you create a dynamic select projection from a generic using Linq in C#?
      1. USewahner
 

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