C# ASP.NET Core Cannot bind to a model of type 'Microsoft.AspNetCore.Http.FormCollection'

Question

I am getting the following error An unhandled exception occurred while processing the request. InvalidOperationException: The 'Microsoft.AspNetCore.Mvc.ModelBinding.Binders.FormCollectionModelBinder' cannot bind to a model of type 'Microsoft.AspNetCore.Http.FormCollection'. Change the model type to 'Microsoft.AspNetCore.Http.IFormCollection' instead.

This is when I use the following code:

[ValidateAntiForgeryToken]
[HttpPost]
public IActionResult Index(Test test, FormCollection formCollection)
{        
    var feesAmountArray = new List<string>();

    foreach (var item in formCollection.Keys.Where(k => k.StartsWith("FeesAmount-")))
    {
        feesAmountArray.Add(formCollection[item].ToString().TrimEnd(','));
    }

    var feesAmount = string.Join(",", feesAmountArray);

    if (ModelState.IsValid)
    {
    }

    return View(test);
}

Within the model Test I am using a [Decimal] attribute which is used in conjunction with a ModelBinder, but I am not wanting to bind to the form in anyway, I just want to bind to the model, so I am a little confused as to why this message is presenting itself.

The code relating to the ModelBinder can be found at:

C# ASP.NET Core ModelBinder not Updating Model

Any help would be much appreciated :-)

Answer 1

Two options:

1. Change your parameter to be IFormCollection
2. Remove it and instead access it through HttpContext.Form