List of ModelExpression to TagHelper

Question

I want to create a custom taghelper which creates display function for a model with multiple values. However, I want to occasionally ignore some values of the model. So ideally I would like to pass a list of ModelExpression values to the taghelper so I know which ones to ignore on the output. This does not seem to be possible.

Example code to demonstrate:

Model to display:

public class Field
    {
        public int Id { get; set; }
        public string Title { get; set; }
        public string Text { get; set; }
        public int Number { get; set; }
        public short Order { get; set; }
        public string Class { get; set; }

In taghelper:

        [HtmlAttributeName("asp-for")]
        public ModelExpression For { get; set; }

        [HtmlAttributeName("asp-ignore")]
        public List<ModelExpression> Ignore { get; set; }

In View:

@model MvcProject.Models.Field

@{
}

<custom-displayforModel asp-for="@Model" asp-ignore="new List<ModelExpression>() { Model.Id, Model.Class}"">
    </custom-displayforModel>

It is possible to pass items like Model.Id and Model.Class individually but as a list I can only produce errors.

List<ModelExpression>() { Model.Id, Model.Class} produces Cannot convert type 'int' to Microsoft.AspNetCore.Mvc.ViewFeatures.ModelExpression

List<ModelExpression>() { Model.Id as ModelExpression } produces Cannot convert type 'int' to 'Microsoft.AspNetCore.Mvc.ViewFeatures.ModelExpression' via a reference conversion, boxing conversion, unboxing conversion, wrapping conversion, or null type conversion

List<ModelExpression>() { (ModelExpression)Model.Id} produces Cannot convert type 'int' to 'Microsoft.AspNetCore.Mvc.ViewFeatures.ModelExpression'

Am I wrong? Is there a possible way to pass these values somehow to the taghelper? Should I try to get and pass the Display name of the properties instead?

Answer 1

ModelExpression accepts any type. You can change List<ModelExpression> to ModelExpression.

    [HtmlAttributeName("asp-ignore")]
    public ModelExpression Ignore { get; set; }

In the view, pass a list.

@{
    var list = new List<Field>
    {
        new Field{ Id=1, Class ="class"}
    };
}

<custom-displayforModel asp-for="@Model" asp-ignore="@list"> </<custom-displayforModel>