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POHow to create an ASP.net MVC user control with unknown generic type parameter?
 

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  1. POHow to create an ASP.net MVC user control with unknown generic type parameter?
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    <p>Currently I'm using a base class for some Customer model classes. As defined as follows</p> <pre><code>public abstract class BaseCustomerModel&lt;T&gt; where T : IUserEntity </code></pre> <p>For further clarification, the IUserEntity contains:</p> <pre><code>public interface IUserEntity { string ErrorMessage { get; } } </code></pre> <p>That property among some other things will be exposed in an ErrorTextControl.ascx:</p> <pre><code>&lt;%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl&lt;(...).Models.BaseCustomerModel&lt;(...).IUserEntity&gt;&gt;" %&gt; &lt;tr&gt; &lt;td colspan="2"&gt;&lt;%: Html.DisplayFor(model =&gt; model.ErrorMessage) %&gt;&lt;/td&gt; &lt;/tr&gt; </code></pre> <p>I'll call the user control like so:</p> <pre><code>&lt;%@ Page Language="C#" Inherits="System.Web.Mvc.ViewPage&lt;(...).Models.MyUserModel&gt;" %&gt; &lt;% if (Model.HasErrors) { Html.RenderPartial("ErrorTextControl", Model); } %&gt; </code></pre> <p>Last piece of code (MyUserEntity implements IUserEntity):</p> <pre><code>public class MyUserModel : BaseCustomerModel&lt;MyUserEntity&gt; </code></pre> <p>Unfortunately this obviously doesn't work, because the generic type can't be implicitly casted to an IUserEntity. Therefore resulting in the following error message in the browser:</p> <blockquote> <p>Exception Details: System.InvalidOperationException: The model item passed into the dictionary is of type '(...).Models.MyUserModel', but this dictionary requires a model item of type '(...).Models.BaseCustomerModel`1[(...).IUserEntity]'.</p> </blockquote> <p>So questions:</p> <ul> <li>Is there any way to define a user control with a generic base class from which the type is not yet known? If yes, how to accomplish such thing?</li> <li>If not, any workaround, common solution or ideas to be able to have a generic user control?</li> </ul> <p>Many thanks.</p>
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    1. USHerman Cordes
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    1. COmonty - you'll need some sort of common interface (apart from IUserEntity ) that will be bound. have you identified this??. i say this because you'll be strongly typing sets of properties, therefore these properties will need to be part of a contract. if it's just the IUserEntity part that needs to be exposed to the ErrorTextControl.ascx, then why not: <%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<IUserEntity>" %> - or am i completely missing the point here :)
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      1. POHow to create an ASP.net MVC user control with unknown generic type parameter?
      1. USjim tollan
    2. COJep, just found out myself too... see the answer I posted.
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      1. POHow to create an ASP.net MVC user control with unknown generic type parameter?
      1. USHerman Cordes
    3. COgood - you know it makes sense!! ;)
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      1. POHow to create an ASP.net MVC user control with unknown generic type parameter?
      1. USjim tollan
 

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