Pass Additional ViewData to DisplayFor Template

Question

I want to pass an object Model.AvailableVerticalType along with the expression and templateName in the call to the HTML Helper DisplayFor. Without passing the object, the DisplayFor() syntax looks like this:

@Html.DisplayFor(o => offer, MVC.Shared.Views.DisplayTemplates.OfferDetail)

The OfferDetail template accepts an object of the type Offer only:

@model DGS.DGSAPI.UI.BusinessModels.Offer

So I need a way to send the AvailableVerticleType through the ViewData. Is it possible? What would be the syntax for passing ViewData in DisplayFor()?

Answer 1

As suggested by user3559349, you can pass an anonymous object into the DisplayFor() method and that get's to be a part of the ViewData dictionary.

In your view:

@Html.DisplayFor(o => offer, "OfferDetail", new {AvailableVerticalType = Model.AvailableVerticalType }

In your OfferDetail template:

(AvailableVerticalType)ViewData["AvailableVerticalType"]

You could also just create a partial view that has a model declared for the AvailableVerticalType and reference that in your main view.

@model AvailableVerticalType

Answer 2

You pass it in ViewDataDictionary, example below:

// optional: if you don't want to use "AdditionalData" magic string
public static class ViewDataKeys
{
    public const string AdditionalData = "AdditionalData";
}

We can use the 2nd overload of DisplayFor and pass the additional data in ViewDataDictionary:

@Html.DisplayFor(m => m.MyModel, new ViewDataDictionary { { ViewDataKeys.AdditionalData, "additional-value" } })

And in your DisplayFor template you can access the ViewDataDictionary like this:

@{
    string additionalData = ViewData[ViewDataKeys.AdditionalData];

    /*
     * if you need to cast the data type:
     * var additionalData = (AdditionalDataType)ViewData[ViewDataKeys.AdditionalData];
     */
}

---

You can also pass multiple additional data, for example:

@Html.DisplayFor(m => m.MyModel, new ViewDataDictionary { 
    { ViewDataKeys.AdditionalData1, "additional-value1" },
    { ViewDataKeys.AdditionalData2, "additional-value2" }
})

Keeping in mind that it is always better to pass the data in a Model.