ValidateFormHandler.cs

public class ValidateFormHandler : ActionMethodSelectorAttribute
{
    /// <summary>
    /// Determines whether the current action is valid for this request.
    /// </summary>
    /// <param name="controllerContext">The controller context.</param>
    /// <param name="methodInfo">The method information.</param>
    /// <returns>Boolean value if request is valid</returns>
    public override bool IsValidForRequest(ControllerContext controllerContext, MethodInfo methodInfo)
    {
        string controller, action;
        if (controllerContext.HttpContext.Request.HttpMethod == "POST")
        {
            // POST
            controller = controllerContext.HttpContext.Request.Form[UnicHelper.ControllerFieldName];
            action = controllerContext.HttpContext.Request.Form[UnicHelper.ActionFieldName];    
        }
        else
        {
            // GET
            controller = controllerContext.HttpContext.Request.QueryString[UnicHelper.ControllerFieldName];
            action = controllerContext.HttpContext.Request.QueryString[UnicHelper.ActionFieldName];
        }
            
        return !string.IsNullOrWhiteSpace(controller)
            && !string.IsNullOrWhiteSpace(action)
            && controller == controllerContext.Controller.GetType().Name
            && methodInfo.Name == action;
    }
}