Am avut de facut o aplicatie cu ASP.NET MVC  – si bineinteles, cu un grid ce lista niste vinzari si cu total.

Asta e ceea ce mi-a pus probleme : totalul … Asa incit, dupa ce am studiat grid-ul de la ASP.NET MVC Contrib , a trebuit sa il extind. Si nu a fost foarte greu. Mai intii , practica -  sintaxa e asemanatoare, doar ca adaug o functie pentru footer :

<% =Html.HtmlGridFooter<Lines>(ViewData.Model.Lines,
        (x) =>
        {
            decimal total = 0;
            foreach (var s in x) { total += s.Total; };   
            return "<tr><td colspan=1 align=right>Total</td><td colspan=1>"+ total.ToString("#.00")+"</td></tr>";
        }

) si de aici incepe grid-ul obisnuit.

Teoria : a trebuit sa extind HtmlTableGridRenderer si sa il atasez de grid …Probabil ca o sa fie nevoie sa am , odata, doi grid renderer?

Cod :

public class HtmlGridFooter<T> : Grid<T>
        where T : class
    {
        public HtmlGridFooter(IEnumerable<T> dataSource, TextWriter writer, ViewContext context) :
            base(dataSource, writer, context)
        {
        }
        public Func<IEnumerable<T>, string> footer
        {
            set
            {
                this.RenderUsing(new FooterHtmlGrid<T>() { actions = base.DataSource, footer = value });
            }
        }

    }
    public class FooterHtmlGrid<T> : HtmlTableGridRenderer<T>
        where T : class
    {
        public IEnumerable<T> actions;
        public Func<IEnumerable<T>,string > footer;
        protected override void RenderGridEnd(bool isEmpty)
        {
            if (footer != null)
            {
                base.RenderText(footer(actions));
            }
            base.RenderGridEnd(isEmpty);
        }
    }

si intr-o clasa statica ar trebui pus:

public static IGrid<T> HtmlGridFooter<T>(this HtmlHelper helper, IEnumerable<T> dataSource, Func<IEnumerable<T>, string> footer)
        where T : class
        {
            HtmlGridFooter<T> g = new HtmlGridFooter<T>(dataSource, helper.ViewContext.HttpContext.Response.Output, helper.ViewContext);
            g.footer = footer;
            return g;
        }