CODEWITHSUNDEEP
asp.net-mvc
house9
house9

Reputation: 20614

ASP MVC Razor view extension methods, how to create 'global' view methods?

I am using Razor view with asp mvc preview 3

I am trying to create some methods which I would like available directly in the views. These are not really Html helper methods so I don't think extending HtmlHelper makes sense?

my goal, be able to call methods in the view i.e.

@HelloWorld(); vs @Html.HelloWorld()

I can get Html.HelloWorld to work by creating an extension method on HtmlHelper

public static class HtmlExtensions
{
    public static string HelloWorld(this HtmlHelper helper)
    {
        return "Hello";
    }
}

I would like to do the same thing but for the view; my problem - what type of object is the view?

Note: I was able to get this to work by defining the methods in the .cshtml page

@functions 
{
    public string HelloWorld()
    {
        return "Hello";
    }
}

@HelloWorld() @* now this works *@

then I tried to put this code my _viewstart.cshtml file thinking it would be available in all views but it was not

if I knew which type the view was I think it could be easily extended, any help appreciated

Upvotes: 19

Views: 14265

Answers (4)

house9
house9

Reputation: 20614

it turns out, the asp runtime is going to define the Execute method at runtime, so the custom view base class must also be abstract

using System;
using System.Web.Mvc;

namespace MyMvcWebApp.Extensions
{
    public abstract class ViewBase<TModel>
        : System.Web.Mvc.WebViewPage<TModel> where TModel : class
    {
        // now this will be available in any view @HelloWorld()
        public string HelloWorld()
        {
            return "Hello from the ViewBase class";
        }
    }
}

this should work with strongly typed views, it looks like with razor all views are strongly typed, when you do not define the type 'dynamic' is used and that is the strong type

also, as Clicktricity stated you then update the web.config (the one under the Views directory)

<pages pageBaseType="MyMvcWebApp.Extensions.ViewBase">

Upvotes: 13

Talley
Talley

Reputation: 561

The best way to call a method with arguments using razor engine is to use helpers. Example: let you have a helper @MakeNote(string content)

Then in cshtml page you just need to call @MakeNote("Hi") and you should be fine.

I was going crazy when I was having problem then google sent me to this page but it did not help. I was trying to load content in html <select> with L2E using razor.

The secret is to create a helper in app_code then use with cshtml.

Upvotes: 1

Rob Kent
Rob Kent

Reputation: 5193

As remarked by others, Razor Views all ultimately inherit from WebViewPage:

public abstract class WebViewPage<TModel> : WebViewPage

You can therefore simply write your extension methods for WebViewPage without creating a new base class or changing the config files, which has been suggested by other answers. For example:

public static class WebViewPageExtensions
{
    public static string HollowWorld(this WebViewPage wvp)
    {
        return "Memento mori";
    }
}

Add a using statement for that namespace to your View and then:

<p>@this.HollowWorld()</p>

Upvotes: 13

Clicktricity
Clicktricity

Reputation: 4209

The default base class for Razor views is specified in the Web.config located in the views directory. Usually it is:

<pages pageBaseType="System.Web.Mvc.WebViewPage">

I've not tried it, but I would suggest inheriting from this base class and adding your own functionality, then adjust the web.config accordingly.

Upvotes: 1

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