ASP Core tag helper with inheritance in model

Question

Let's say we have these simplified models:

public class Person {
   public string Address {set;get;}
}

public class Student: Person {
   public float Grade {set;get;}
}
public class Teacher: Person {
   public string Department {set; get;}
}

Now we want to have a create page for student and teacher. my question is how we can use benefits of inheritance to create only one page for student and teacher?

I tried this:

@model Person

@{
    bool isStudent = Model is Student;
}

<form asp-action="Create">
    <div class="form-horizontal">
    @if (isStudent)
    {
        <div class="form-group">
            <label asp-for="((Student)Model).Grade" class="col-md-2 control-label"></label>
            <div class="col-md-10">
                <input asp-for="((Student)Model).Grade" class="form-control" />
                <span asp-validation-for="((Student)Model).Grade" class="text-danger"></span>
            </div>
        </div>
   } else {
        <div class="form-group">
            <label asp-for="((Teacher)Model).Department" class="col-md-2 control-label"></label>
            <div class="col-md-10">
                <input asp-for="((Teacher)Model).Department" class="form-control" />
                <span asp-validation-for="((Teacher)Model).Department" class="text-danger"></span>
            </div>
        </div>
   }
   <div class="form-group">
         <label asp-for="Address" class="col-md-2 control-label"></label>
         <div class="col-md-10">
             <input asp-for="Address" class="form-control" />
             <span asp-validation-for="Address" class="text-danger"></span>
         </div>
   </div>
   <div class="form-group">
            <div class="col-md-offset-2 col-md-10">
                <input type="submit" value="Create" class="btn btn-success" />
            </div>
        </div>
    </div>
</form>

but it does not allow asp-for="((Student)Model).Grade"

HamedH · Accepted Answer · 2017-07-11 09:03:12Z

2

found it:

According to https://learn.microsoft.com/en-us/aspnet/core/mvc/views/working-with-forms#the-input-tag-helper "@" character can be used to start an inline expression

So this is correct:

asp-for="@(Model as Student).Grade"

answered Jul 11, 2017 at 9:03

HamedH

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Comments

Set · Accepted Answer · 2017-07-08 07:11:58Z

0

Look into this ViewModel with inheritance in ASP .NET Core discussion on github:

It suggests a solution where a subclass tag-helper surround the fields that are specific to each subclass. That fields are rendered either if the model is null or if a specific subclass of that class is passed.

Here is the example: link

answered Jul 8, 2017 at 7:11

Set

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