JSON.stringify causing problems with decimal values in MVC Action parameters

PROBLEM

You may have noticed some time your MVC web site behave crazy when you are passing decimal values to a action. This decimal problem arises if you are using "JSON.stringify" to get JSON string to send with HTTP POST to a MVC controller action.

What causing the issue is JSON.stringify will behave as follows.

15.123 => 15.123
15.00 => 15

EX : {a:15.123, b:15.00} => "{a:15.123, b:15}"

When this json string reach MVC default model binder, it will convert 15.123 parameter as a decimal and 15 into a integer or long according to your value.

SOLUTION

1) Convert your decimal values to string before you pass it to JSON.stringify
2) Use a custom model binder for decimals (more info here : posted by Josh)

using System;
using System.Globalization;
using System.Web.Mvc;

public class DecimalModelBinder : IModelBinder
{
    public object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
    {
        ValueProviderResult valueResult = bindingContext.ValueProvider
            .GetValue(bindingContext.ModelName);
        ModelState modelState = new ModelState { Value = valueResult };
        object actualValue = null;
        try
        {
            actualValue = Convert.ToDecimal(valueResult.AttemptedValue,
                CultureInfo.CurrentCulture);
        }
        catch (FormatException e)
        {
            modelState.Errors.Add(e);
        }

        bindingContext.ModelState.Add(bindingContext.ModelName, modelState);
        return actualValue;
    }
}