Spark - Recursive rendering of partial files not possible (but it is!)

We've been using the Spark View Engine a lot at work. I absolutely love it. Our front end developers love it (they don't need to re-learn something like we had to for NHaml) and if they don't want to use Spark's features, standard HTML works without problems.

During one project, I was making some contextual menus. I wanted to call a Spark partial recursively in order to not repeat myself & keep things flexible for the future. Unfortunately Spark specifically disallows this. If you try it, you will get an Exception that states "Recursive rendering of partial files not possible".

Well that just sucks. I understand the limitation in the View Engine itself but there is a way around it. Not super elegant but definitely functional without sacrificing anything other than style.

I posted the following example in the Spark project itself. The trick is using the HtmlHelper's RenderPartial method.

Let's say we have a partial called: navigation.spark.

< --- Contents of: navigation.spark --- >
<viewdata navItem="Models.NavigationItem" />

<li><a if="navItem != null" href="${navItem.Url}">${navItem.Name}</a></li>

<ul if="navItem.Children.Count > 0" >
  <for each="var child in navItem.Children" >
    #{Html.RenderPartial("_navigation.spark", new { child });}
  </for>
</ul>


And the page that you want to list navigation items, simply do:

<viewdata navigationItems="List<Models.Navigation>" />

<navigation for="var nav in navigationItems" navItem="nav" />



Now you can call the Partial recursively without issues.

Comments

Post a Comment

Popular posts from this blog

Fluent NHibernate - Incorrect syntax near the keyword 'Group'

I have to share this. I spent a good amount of time searching around Fluent NHibernate for a way to escape columns in the generated SQL while still using AutoMapping. My initial configuration looked like: Fluently.Configure() .Database(MsSqlConfiguration.MsSql2005.ConnectionString( c => c.Is(ConfigurationManager.ConnectionStrings["Something"].ConnectionString))) .Mappings(x => x.AutoMappings.Add(AutoPersistenceModel.MapEntitiesFromAssemblyOf () .WithSetup(convention => { convention.FindIdentity = p => p.Name == p.DeclaringType.Name + "Id"; convention.GetComponentColumnPrefix = type => type.Name + "Id"; } ) .BuildSessionFactory() This works great, but I had a property in my class (SomeType) that is called Group. This was causing the SqlException: Incorrect syntax near the keyword 'Group' (others would be like: Incorrect syntax near the keyword 'User' or Incorrect syntax near the keyword ...
Read more

Fluent NHibernate + Encrypting Values

I recently created two CLR User Defined Functions for SQL Server 2005 (written in C#) to decrypt & encrypt a given string (based on a hard-coded key). select dbo.EncryptString('Testing') -- Returns: Fjfds243qcm43fsdj2343== select dbo.DecryptString('Fjfds243qcm43fsdj2343==') -- Returns: Testing Pretty simple stuff. This will allow the user with enough access to pull encrypted data out of the database and provide the ability to restrict decryption to other SQL users. Now to implement this in code... Because it's awesome, Fluent NHibernate has a method called FormulasIs that assists in building out values using SQL. public class User { public virtual int Id { get; set; } public virtual DateTime DateOfBirth { get; set; } } public sealed class UserMap : ClassMap { public UserMap() { WithTable("dbo.[User]"); Id(x => x.Id, "[ID]"); Map(x => x.DateOfBirth, "DOB").FormulaIs("dbo.DecryptString(DOB)"); ...
Read more

MapReduce in C# using Task Parallel Library

Back in August I starting playing with a C# implementation of Google's MapReduce algorithm. The implementation was based on something Stephan Brenner did, although I completely refactored it. Today I added a little bit of logic to split up the actual execution of Map & Reduce in this implementation using the Task Parallel Library in .NET 4.0. Check out the source code for MapReduce in C# on GitHub. Below is an excerpt from the Tests on how to implement the library. Counting Words in Files public static List<KeyValuePair<string, int>> Map(FileInfo document, string text) { var items = text.Split('\n', ' ', '.', ',','\r'); return items.Select(item => new KeyValuePair<string, int>(item, 1)).ToList(); } public static List<int> Reduce(string word, List<int> wordCounts) { if (wordCounts == null) return null; var result = new List<int> { 0 }; foreach (var value in wordC...
Read more