ASP.NET MVC 3 dynamic form generation

Question

I am trying to generate a form at run-time. I have ended up with this approach

@using (Html.BeginForm()) {
    @foreach (var propertyInfo in typeof(MvcApplication1.Models.LogOnModel).GetProperties()) {
        if (propertyInfo.PropertyType == typeof(Boolean)) {
            Html.CheckBoxFor(m => new PropertyWrapper<Boolean>(propertyInfo, Model).Property);
        }
        else if (propertyInfo.PropertyType == typeof(String)) {
            Html.TextBoxFor(m => new PropertyWrapper<String>(propertyInfo, Model).Property);
        }
        ...
    }
}

With this class to allow the [ElementType]For() methods to work (they need a reference to a property which can't be retrieved using reflection).

public class PropertyWrapper<T> {
    private PropertyInfo _propertyInfo;
    private Object _instance;

    public PropertyWrapper(PropertyInfo propertyInfo, Object instance) {
        _propertyInfo = propertyInfo;
        _instance = instance;
    }

    public T Property {
        get { return (T)_propertyInfo.GetValue(_instance, null); }
        set { _propertyInfo.SetValue(_instance, value, null); }
    }
}

I get the following error

System.Reflection.TargetException: Non-static method requires a target.

because instance parameter of PropertyWrapper constructor is null. Am I missing something? Is this even possible?

I didn't realize they would be bound automatically! If you make your comment an answer I'll accept. — Nick Strupat
– Nick Strupat, Commented Apr 2, 2012 at 18:30

Darin Dimitrov · Accepted Answer · 2012-04-02 18:29:17Z

3

Forget about strong typing, the XXXFor helpers and lambda expressions. Once you start the Reflection game you have to play it till the end.

The XXXFor helpers work with very simple expressions such as property accesses.

m => new PropertyWrapper<String>(propertyInfo, Model).Property is far beyond the capabilities of those helpers.

answered Apr 2, 2012 at 18:29

Darin Dimitrov

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Comments

Kyle Trauberman · Accepted Answer · 2012-04-02 18:31:19Z

1

Why not use the non "for" methods? @Html.CheckBox() for example. Just pass the name of the property to the method, and model binding will still work after postback

answered Apr 2, 2012 at 18:31

Kyle Trauberman

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