Mattew Abbot has declarative helpers working he says in his article, which Niels Hartvig mentions was an inspiration writing the Umbraco Razor engine. Could be Mattew updated his code later, he says "The updated project is attached" at the end of the article.

@using System.Collections.Generic
@helper Title(string title) {
    @title
}
@helper DisplayItems(IEnumerable items) {
    @if(items != null) {
        @foreach(string item in items) {
            
@item

        }
    }
}

When I try (a very simple @helper) I get this error

System.ArgumentNullException: Value cannot be null. Parameter name: typeName at System.Web.Razor.Generator.CSharpCodeWriter.EmitStartConstructor(String typeName) at System.Web.Razor.Generator.RazorCodeGenerator.VisitSpan(HelperHeaderSpan span) at System.Web.Razor.Generator.RazorCodeGenerator.TryVisitSpecialSpanCore(Span span) at System.Web.Razor.Generator.RazorCodeGenerator.VisitSpan(Span span) at System.Web.Razor.Parser.ParserContext.EndBlock() at System.Web.Razor.Utils.DisposableAction.Dispose() at System.Web.Razor.Parser.HtmlMarkupParser.ParseRootBlock(Tuple`2 nestingSequences, Boolean caseSensitive) at System.Web.Razor.Parser.RazorParser.Parse(LookaheadTextReader input, ParserVisitor visitor) at umbraco.MacroEngines.Razor.RazorCompiler.Compile(String className, String template, Type modelType) in d:\TeamCity6\buildAgent\work\f90b8294889fbe14\umbraco.MacroEngines.Juno\Razor\RazorCompiler.cs:line 62 at

Added to codeplex http://umbraco.codeplex.com/workitem/29817

Ah, great, it works fine in Umbraco 4.6.1! 

Here's the full sitemap sample:

@helper traverse(int nodeid) { 
 @{
  Node n = new Node(nodeid);
  if (n.Children.Count>0) {
   <ul>
    @foreach (Node c in n.Children) {
    <li>
     @c.Name  
     @traverse(c.Id)
    </li>
    }
   </ul>  
  }
 }
}
<h1>Sitemap</h1>
@traverse(-1)

I needed to add the extra @{ } , could perhaps be made a bit more elegant? 

oh, I forgot - add this in top of it all

@using umbraco.NodeFactory           

(umbraco.presentation.nodeFactory is now obsolete)

Have you checked out AncestorOrDefault to see if you can just do it with lambda statements?

Hm... Cannot get pass the "Cannot use a lambda expression as an argument to a dynamically dispatched operation without first casting it to a delegate or expression tree type" error unfortunately.

Ahh yeah, you probably have to set the model type of the razor script. Damn...

So it isn't possible to use lambda expressions?

Getting the same error when trying to do

@foreach (var p in @Model.Children.Where(c => c.umbracoNaviHide != "1"))
{
   <li>@p.Name</li>
}

Or am I doing something wrong?

Yeah, would be cool to use DynamicNode,

meanwhile here's a sample using uQuery (uComponents):

@using uComponents.Core
@using uComponents.Core.uQueryExtensions
@using System.Linq
@using umbraco.presentation.nodeFactory
@helper traverse(Node n) 
{
 @{
   var c = n.GetDescendantNodes().Where(node=>!node.GetPropertyAsBoolean("umbracoNaviHide"));
   if (c.Any())
   {
    <ul>
    @foreach (var cc in c)
    {
        <li><a href="@cc.Url">
            @cc.Name
        </a>
            @traverse(cc)
        </li>
     }
    </ul>
    }
   }
}
@traverse(uQuery.GetRootNode())

To minimize the code in a Razor script it should be possible to add the namespaces in web.config instead, right? http://www.west-wind.com/Weblog/posts/2287.aspx

Hi,

The GetDescendantNodes() method from the route node will recurse the whole tree - so to match the previous example GetChildNodes() would work.

DynamicNode looks interesting ! is that a part of LinqToUmbraco ?

Cheers,

Hendy

Hi oh, right, thanks. I just started with uQuery, really useful, thanks for sharing it :-)

A must read for all who, like me, need to learn more about it: http://ucomponents.codeplex.com/wikipage?title=uQuery .

DynamicNode is not a part of Linq2Umbraco as far as I know. It came with Juno and the IMacroEngine. A great idea, adding some useful methods to nodes + dynamically adding node properties as methods (as shown in Niels and Aarons examples). But writing lambdas with dynamic objects obviously (?) arent as easy as one would like.

Here's a script I converted to Razor (from a Python one) to point out some gotchas about Razor in Umbraco

@using System

@using System.Web
@using umbraco.NodeFactory
<h2>Lista h&auml;r</h2>
@{
 string querystringId = umbraco.library.RequestQueryString("id");
 int id;
 if (Int32.TryParse(querystringId, out id))
 {
   var n = new Node(id);
   foreach (Node c in n.Children)
   {
      <li>@c.Name</li>
   }
 }
}

1. The engine doesnt give you any namespaces by default. I add System and System.Web to be able to use common stuff like Parse and HtmlEncode. Namespaces cannot be added to web.config as I hoped (see earlier post in this thread).
2. You never would like to save a Razor script with syntax checking skipped. If the script does not validate it simply won't work.
3. HtmlEncoding does not happen automatically, so Swedish characters like åäö wont display correctly. I also tried HtmlEncoding my String, but that didnt work either (I got "?"'s).
4. The @ - syntax is not exactly the same as the one MVC3 is using, the most obvious thing is the oneliners, so @var x = "x" does not work. The easy fix is to enclose all c# code in @{ }, like in my example.

Hi Jonas,

Good to know that Razor supports namespace declarations defined in the web.config.

Cheers,

Hendy

I really liked to use DynamicNode, and tried to create one with:

@using umbraco.MacroEngines
@using umbraco.NodeFactory
@{
  var dn = new DynamicNode(new Node(id));
}

However I get the error The type name 'Compilation' does not exist in the type 'umbraco.MacroEngines.RazorEngine' . And I cannot find that one?

Sorry Hendy - cannot. I corrected my post now. The Razor engine does not care about the added namesspaces in web.config.

Here's an corrected and updated sitemap sample with the use of both Where and OrderBy.

@using System
@using System.Web
@using uComponents.Core
@using uComponents.Core.uQueryExtensions
@using System.Linq
@using umbraco.presentation.nodeFactory

@* Helper function for the node traversion *@
@helper traverse(Node n)
 {
 @{
   var c = n.GetChildNodes().Where(node=>!node.GetPropertyAsBoolean("umbracoNaviHide")).OrderBy(node=>node.Name);
   if (c.Any())
   {
    <ul>
    @foreach (var cc in c)
    {
        <li><a href="@cc.Url">
            @cc.Name
        </a>
            @traverse(cc)
        </li>
     }
    </ul>
    }
   }
}


@* Render the sitemap *@
<h2>Sitemap</h2>
@traverse(uQuery.GetRootNode())

I continue my experiments with the Razor engine,

sometimes it's indeed necessary to skip tests while saving a Razor macro. For example when a macro is querying for  current node using nodeFactory or GetCurrent() using uQuery. For example to get the acestor on a certain depth (level):

  var startNode = uQuery.GetCurrentNode().GetAncestorOrSelfNodes().FirstOrDefault(node => node.GetDepth()==2);

Last snippet for the day, top navigation (starting on level 2)

@using uComponents.Core
@using uComponents.Core.uQueryExtensions
@using System.Linq

@{
  var startNode = uQuery.GetCurrentNode().GetAncestorOrSelfNodes().FirstOrDefault(node => node.GetDepth()==2);
  var children = startNode.GetChildNodes().Where(node=>!node.GetPropertyAsBoolean("umbracoNaviHide"));
    <ul>
    @foreach (var c in children)
    {
      string css="";
      if (c.Id == uQuery.GetCurrentNode().Id) css="class =\"selected\"";
      <li @css>      
        <a href="@c.Url">
            @c.Name
        </a>
      </li> 
    }
    </ul>
}

Playtime continues. I made complete login/logout macro script in Razor. Works pretty good actually. Would need some more attention before it makes a package though.

@using System.Web  
@using System.Web.Security

@helper LoginForm()
{
  <form>
  <label for="name">Username:</label>
  <input type="text" id="username" name="username"/>
  <label for="password">Password:</label>
  <input type="password" id="password" name="password"/>
  <input type="submit" id="submit" name="submit" value="login"/>
  </form>
}

@helper LogoutForm()
{
  <form><input type="submit" id="submit" name="submit" value="logout"/></form>
}

@{
  var request = HttpContext.Current.Request;
  var isSubmitLogin = (request.HttpMethod=="POST" && request.Form["submit"]=="login");
  var isSubmitLogout = (request.HttpMethod=="POST" && request.Form["submit"]=="logout");
  var currentUser = Membership.GetUser();
  
  if (currentUser!=null)
   {    
    if (!isSubmitLogout)
     {
       <p>Logged in : @currentUser.UserName</p>
       @LogoutForm()
     }
    else
     {
       FormsAuthentication.SignOut();
       FormsAuthentication.RedirectToLoginPage();
     } 
   }

  if (currentUser==null)
   {
    if (!isSubmitLogin)  
     {
       @LoginForm()
      }
    else
     {
      string username=request.Form["username"];
      string password=request.Form["password"];
      if (Membership.ValidateUser(username, password))
      {
        FormsAuthentication.RedirectFromLoginPage(username, true);
      }
      else
      {
        <p> Login failed for @username</p>
        @LoginForm()
      }
     }       
    }
  }

Cool - now it's possible to add default namespaces in web.config

  <system.web.webPages.razor>
    <host factoryType="umbraco.MacroEngines.RazorUmbracoFactory, umbraco.MacroEngines" />
    <pages pageBaseType="umbraco.MacroEngines.DynamicNodeContext">
      <namespaces>
        <add namespace="Microsoft.Web.Helpers" />
        <add namespace="umbraco" />
        <add namespace="Examine" />
        <add namespace="umbraco.MacroEngines" />
        <add namespace="uComponents.Core" />
        <add namespace="uComponents.Core.uQueryExtensions" />
      </namespaces>
    </pages>

Hi,

I've noticed that when moving the namespace registrations into the web.config, intellisense disappears when editing the cshtml file, is there a way keep intellisense but not have to put the using statements in each file ?

Thanks,

Hendy

Intellisense? How activate it in Umbraco?

is working on a reply...