MVC 3 doesn't bind nullable long

Question

I made a test website to debug an issue I\'m having, and it appears that either I\'m passing in the JSON data wrong or MVC just can\'t bind nullable longs. I\'m using the latest

Answer 1

You can use this model binder class

public class LongModelBinder : IModelBinder
{
    public object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
    {
        var valueResult = bindingContext.ValueProvider.GetValue(bindingContext.ModelName);
        if (string.IsNullOrEmpty(valueResult.AttemptedValue))
        {
            return (long?)null;
        }
        var modelState = new ModelState { Value = valueResult };
        object actualValue = null;
        try
        {
            actualValue = Convert.ToInt64(
                valueResult.AttemptedValue,
                CultureInfo.InvariantCulture
            );
        }
        catch (FormatException e)
        {
            modelState.Errors.Add(e);
        }
        bindingContext.ModelState.Add(bindingContext.ModelName, modelState);
        return actualValue;
    }
}

In Global.asax Application_Start add these lines

ModelBinders.Binders.Add(typeof(long), new LongModelBinder());
ModelBinders.Binders.Add(typeof(long?), new LongModelBinder());