Question

I found all value passed by Model is not trimmed in ASP.net MVC3

Is there a way to:

1. Apply a trim() on every field in Model (all string fields, at least; but all form fields are string before processed by Model, so better trim them all)
2. Must before ModelState.IsValid() (because I often found code stucked at weird ModelState.IsValid and later found because the form item did not be trimmed.)

Thanks.

Answer 1

You’ll have to create a custom model binder to trim any model property that is a string.

References:
Custom model binding using IModelBinder in ASP.NET MVC
Iterating on an ASP.NET MVC Model Binder
6 Tips for ASP.NET MVC Model Binding
A Better Model Binder

Basically, you can take one of two approaches:

1. Implement the IModelBinder interface
2. Subclass the DefaultModelBinder class

Example

public class StringTrimmingBinder : DefaultModelBinder
{
    public override object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
    {
        // trim your string here and act accordingly

        // in the case the model property isn't a string
        return base.BindModel(controllerContext, bindingContext);
    }
}