Question

Currently in MVC, we have to define columns manually whenever we want to list out items:

<tr>
    <td>
        @Model.Name
    </td>
    <td>
        @Model.Age
    </td>
    <td>
        @Model.Gender
    </td>
</tr>

What I want to do however, is to have a ViewModel where we specify which columns should be used, something like:

var model = new PersonViewModel(
    // List of persons
    CollectionOfPersons,
    // List of columns that we want to display
    new Expression<Func<Person, object>>[]
    {
        x => x.Name,
        x => x.Age,
        x => x.Gender
    });

Then in our view, all I need to do is:

<tr>
    // Model.Predicates is our ViewModel's selected columns
    @foreach(var predicate in Model.Predicates)
    {
        <td>
            // This would basically loop each pre-defined lambda expression in our ViewModel
            @Html.DisplayFor(predicate)
        </td>
    }
</tr>

I have to admit I have a very weak understanding of expressions, and I have so far been unsuccessful in looking for information. Does anyone have any idea if this is possible to do?

Answer 1

Seems like the html helpers don’t work like that (passing in the expression as a variable). The compiler explicitly needs an expression to be able to determine the TModel and TResult types to be able to work.