Part 4 of the feature walkthrough continues with features
available in the TAFKA 4.6.2 release.
Today, I'm covering .Where to filter nodes and .OrderBy to order
RC1 is just around the corner and there's a bunch more features
coming - i'll try and cover those too when they come out -
We've got more functions for navigating your tree, slightly better
support for some .Where edge cases, .Where extension methods and
Taking this implementation to the next level, we quickly found
we wanted to select a random number of elements which should be
visible but were still published.
An example is if you have a boolean property (defined as the
True/False data type) on your document type that indicates if an
item should be featured or not.
With DynamicObject (DynamicNode too, because it inherits from),
the c# compiler / razor parser doesn't allow you to use the
familiar lambda syntax to filter your sets.
This is because we now return a DynamicObject [DynamicNodeList] to
allow method chaining.
This will not work in 4.6.1 or 4.7.
@Model.Children.Where(item => item.shouldBeFeatured);
//Lambda's cannot be used against Dynamic Objects
With the new 4.7 syntax, you can now use .Where to filter your
To do this, we took the string parser from the 2008 linq samples
and then added support for working with DynamicObjects
I saved the best for last!
A simplistic filter by a single boolean:
A longhand filter, demonstrating the equality operator and type
@Model.Children.Where("shouldBeFeatured == true")
@Model.Children.Where("shouldBeFeatured != true")
Using GreaterThan against a numeric property
@Model.Children.Where("catCount > 1")
Using Modulus (to get the remainder of a number)
(will return any children where the number of cats is even)
@Model.Children.Where("catCount % 2 == 0")
Using string comparisons and boolean logic (|| [or], &&
[and]) - also shows how to nest strings
@Model.Children.Where("menuType == \"Top Menu\ || menuType == \"Bottom Menu\"")
Chaining into your own extension method
(will return 8 randomly selected nodes which are marked as
Passing Variables from outer scope into the .Where
If you need to access a variable from outside the scope (e.g. a
number etc) and don't want to pass it as a constant,
var maxLevelForSitemap = 4;
var values = new Dictionary<string,object>();
values.Add("maxLevelForSitemap", maxLevelForSitemap) ;
var items = node.Children.Where("ShouldBeVisible == true && Level <= maxLevelForSitemap", values);
We have also added support for OrderBy, this lets you sort your
nodesets by the properties on the nodes themselves.
Simplistic ordering by a single property:
More complex ordering by multiple properties, with
@Model.Children.OrderBy("catCount, colour desc")
Warning: There's a small bug in the 4.7 beta
which means you can't order by a single descending column.
This is fixed in RC1.
That pretty much wraps up my additions to Razor in 4.7beta,
hopefully the new syntax improves your ability to work with razor
to build websites with umbraco :)
Some more parts to come once the RC is released
I'm Gareth Evans, Follow me at @agrath on twitter, and here's a
The new Razor forum on our.umbraco: http://our.umbraco.org/forum/developers/razor
Codeplex for any feature requests or bugs: http://umbraco.codeplex.com/
Read more from the Umbraco Razor walkthrough series