Question

I have a View that is displaying data from a list of object that I send it. These objects are all the same base class, but can be a number of different derived types. so, I have:

class Item { public string Description {get;set;}
class VideoItem : Item { public int VideoId {get;set;} }
class PdfItem : Item { public pdfLocation {get;set;} }

I display these all in a single list and would like to be able to have one Controller Method that I can call that will handle each one of these. Having overloads for the method would be fine as well.

I have it wired in as an ActionLink, but I can’t figure out how to pass the entire object to the controller. When I try to pass the class, it only passes the classname (i’m assuming it’s using the .ToString() method on it.

I could use some sort of unique id and then requery the database and recreate the object, but it seems that if I already created the object, I should be able to pass it to a controller intact, no?

Maybe ActionLink isn’t the best solution. I dont care how the controller gets called.

ideas?

Answer 1

Something like this can work for you (assuming you want to display the content of each item as a link):

Create a custom HtmlHelper method:

public static class LinkExtensions
{
    public static MvcHtmlString CustomActionLink(this HtmlHelper htmlHelper, Item item )
    {
        MvcHtmlString returnString = "";

        if(item is VideoItem) 
        {
            VideoItem currentItem = item as VideoItem;
            returnString = htmlHelper.ActionLink(currentItem.VideoId, "Video", "Item");
        }        
        if(item is PdfItem) 
        {
            PdfItem currentItem = item as PdfItem;
            returnString = htmlHelper.ActionLink(currentItem.pdfLocation, "Pdf", "Item");
        }
        else
        {
            returnString = htmlHelper.ActionLink(currentItem.Description, "Item", "Item");
        }

        return returnString;
    }
}

Use it like this (assuming itemList is a List<Item> type list):

<%= foreach(var item in itemList) { Html.CustomActionLink(item) } %>

NOTE: i did not run this code so some tweaking may be necessary.