Web Page Extensions to Associate Domain Models With Web Forms

namespace System.Web.UI
{
    using System.Reflection;

    /// <summary>
    /// Base class for all srongly typed .aspx view pages.
    /// </summary>
    /// <typeparam name="T">Type of the domain model object.</typeparam>
    public abstract class ViewPage<T> : Page
    {
        ModelStateValidator<T> modelState;

        /// <summary>
        /// Get or set domain model type associated with this view page.
        /// </summary>
        protected virtual T Model
        {
            get;
            set;
        }

        /// <summary>
        /// Get html helper object that provides support for rendering html elements.
        /// </summary>
        protected virtual HtmlHelper<T> Html
        {
            get
            {
                return new HtmlHelper<T>(Model, ModelState);
            }
        }

        /// <summary>
        /// Get model state validator dictionary object that contains model-validation errors.
        /// </summary>
        protected virtual ModelStateValidator<T> ModelState
        {
            get
            {
                if (modelState == null)
                {
                    modelState = new ModelStateValidator<T>(Model);
                }
                return modelState;
            }
        }

        /// <summary>
        /// Raises the System.Web.UI.Control.Init event to initialize the page.
        /// </summary>
        /// <param name="e">System.EventArgs containing event data.</param>
        protected override void OnInit(EventArgs e)
        {
            T model = Activator.CreateInstance<T>();            
            if (this.IsPostBack)
            {
                string modelName = typeof(T).Name;
                HttpRequest request = HttpContext.Current.Request;               
                foreach (PropertyInfo property in typeof(T).GetProperties())
                {
                    if (request[modelName + "_" + property.Name] != null)
                    {
                        property.SetValue(model, Convert.ChangeType(request[modelName + "_" + property.Name], property.PropertyType), null);
                    }
                }                
            }
            Model = model;
            base.OnInit(e);
        }
    }
}