C# – Custom model binder for a property

asp.net-mvcccustom-model-bindermodel-binding

I have the following controller action:

[HttpPost]
public ViewResult DoSomething(MyModel model)
{
    // do something
    return View();
}

Where MyModel looks like this:

public class MyModel
{
    public string PropertyA {get; set;}
    public IList<int> PropertyB {get; set;}
}

So DefaultModelBinder should bind this without a problem. The only thing is that I want to use special/custom binder for binding PropertyB and I also want to reuse this binder. So I thought that solution would be to put a ModelBinder attribute before the PropertyB which of course doesn't work (ModelBinder attribute is not allowed on a properties). I see two solutions:

  1. To use action parameters on every single property instead of the whole model (which I wouldn't prefer as the model has a lot of properties) like this:

    public ViewResult DoSomething(string propertyA, [ModelBinder(typeof(MyModelBinder))] propertyB)

  2. To create a new type lets say MyCustomType: List<int> and register model binder for this type (this is an option)

  3. Maybe to create a binder for MyModel, override BindProperty and if the property is "PropertyB" bind the property with my custom binder. Is this possible?

Is there any other solution?

Best Answer

override BindProperty and if the property is "PropertyB" bind the property with my custom binder

That's a good solution, though instead of checking "is PropertyB" you better check for your own custom attributes that define property-level binders, like

[PropertyBinder(typeof(PropertyBBinder))]
public IList<int> PropertyB {get; set;}

You can see an example of BindProperty override here.

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