ASP.NET MVC Beta - Setting properties on ViewControls

In ASP.NET MVC Beta, it isn’t possible to set properties on partials when calling them with Html.RenderPartial.

Rusty Zarse blogged about a useful ViewData helper class, which allows you to set properties by passing values to the partial through the ViewData.

I’ve extended this slightly to enable the following syntax:

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<% Html.RenderPartial("YUIDataTable",
               ViewDataDictionaryBuilder.Create(
                      new
                      {
                        DataTableId = "QuoteDataTable",
                        ConfigNamespace = "QuoteDataTableConfig",
                        HideFilter = true
                       }));%>

Which sets properties on a ViewUserControl like this:

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     public partial class YUIDataTable : ViewUserControl
    {
        public string ConfigNamespace { get; set; }
        public string DataTableId { get; set; }
        public bool HideFilter { get; set; }
 
        protected void Page_Load(object sender, EventArgs e)
        {
            ViewDataDictionaryBuilder.SetPropertiesToViewDataValues(this);
        }
    }

Here is the full helper code.

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using System;
 
namespace MvcHelpers
{
    ///
    /// With thanks to http://www.vitaminzproductions.com/technology-blog/index.php/2008/11/12/setting-properties-using-aspnet-mvc/
    ///
    public static class ViewDataDictionaryBuilder
    {
        public static System.Web.Mvc.ViewDataDictionary Create(object data, ModelType model) where ModelType : class
        {
            return (System.Web.Mvc.ViewDataDictionary)CreateInternal(new System.Web.Mvc.ViewDataDictionary(model), data);
        }
 
        public static System.Web.Mvc.ViewDataDictionary Create(object data, object model)
        {
            return CreateInternal(new System.Web.Mvc.ViewDataDictionary(model), data);
        }
 
        public static System.Web.Mvc.ViewDataDictionary Create(object data)
        {
            return CreateInternal(new System.Web.Mvc.ViewDataDictionary(), data);
        }
 
        private static System.Web.Mvc.ViewDataDictionary CreateInternal(System.Web.Mvc.ViewDataDictionary dictionary, object data)
        {
            AddPropertiesToViewData(dictionary, data);
            return dictionary;
        }
 
        private static void AddPropertiesToViewData(System.Web.Mvc.ViewDataDictionary dictionary, object data)
        {
            if (data == null) return;
 
            System.Reflection.PropertyInfo[] properties = data.GetType().GetProperties();
 
            foreach (var property in properties)
            {
                dictionary.Add(property.Name, property.GetValue(data, null));
            }
        }
 
        public static void SetPropertiesToViewDataValues(System.Web.Mvc.ViewUserControl viewUserControl)
        {
            foreach (var property in viewUserControl.GetType().GetProperties())
            {
                if (viewUserControl.ViewData[property.Name] != null)
                    property.SetValue(viewUserControl, Convert.ChangeType(viewUserControl.ViewData[property.Name], property.PropertyType), null);
            }
        }
 
    }
}

Hope that’s useful to you!

Announcing the TDD TestHelpers opensource project

Whenever I start working on a project; I invariably find myself writing a collection of TDD test helper methods.  I quick survey of other TDDers reveals the same; and thus the birth of my latest opensource project, TestHelpers (http://code.google.com/p/testhelpers/).

The aim of the project is to centralise all those little test helper methods you end up creating into a useful assembly you can use to jumpstart your next project.  Things like:

• Comparers
  • Generic object comparers
  • DataSet comparers
• Test Data generators
  • Builder pattern
• Automocking containers

For example, I’ve just added an “AssertValues” functor; which helps you check whether the values of who object instances are the same. 

One area I keep using asserts like this is in integration tests; where I want to check that the objects I’m persisting to the database via my ORM actually end up in the database in a non-mangled form.  In this case, I new up entityA, persist it, reload it into entityB and then need to check that all the values in entityB are the same as those in entityA.

A standard Assert.AreEqual will fail, because entityA and entityB are different instances.  But, my helper method AssertValues.AreEqual will pass, because it checks the (serialized) string values of entityA and entityB.

Here is another, simpler example to illustrate the concept.

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    [TestFixture]
    public class StandardObjectsTests
    {
        public class StringContainer
        {
            public string String1 { get; set; }
            public string String2 { get; set; }
        }
 
        [Test]
        public void ObjectsWithSameValue_ShouldBeEqual()
        {
            var stringContainer1 = new StringContainer {String1 = "Test String1", String2 = "Test String 2"};
            var stringContainer2 = new StringContainer {String1 = "Test String1", String2 = "Test String 2"};
 
            Assert.AreNotEqual(stringContainer1, stringContainer2);
 
            AssertValues.AreEqual(stringContainer1, stringContainer2);
        }
   }

I’m sure you have a bunch of similar helper methods lying about your projects.

How about contributing them to the TestHelper project?

ALT.NET; London; 13 Sept 2008

Intro

Debate over what ALT.NET is; should it have a set of guiding principles like the Agile manifesto?

Continuous integration & deployment

There seemed to be 3 major areas where people encountered difficulties doing continuous integration & deployment.

1. Configuration files
2. DB schema migrations
3. Data migrations.

When to make technical stories?

During initial sprint planning, stories correspond to user features, and typically follow a

As a [user type]
I can [some action]
So that [some benefit]

structure.

Its important to keep the stories focused on features, rather than on tasks; because we need the users / product owner to be able to decide which stories to add or remove.  (A user cannot decide which tasks to add or remove, because the dependancies aren’t obvious).

However, during development of a particular story, you will often come across an area of the code that needs to be refactored.  A classic example is the case of removal of duplication; where as the design has evolved we discover additional areas of common functionality.

It can be tempting to attempt to work this refactoring into the current story, and if the refactoring is relatively small, this is a good idea.

However, in many cases the refactoring is too large to do without increasing the complexity of the story so much that it might not get finished in the current sprint.

This is the time to create a new “technical story”, which encompasses the refactoring (and perhaps any related work).

Its important that this block of work becomes a story to increase its visibility to the team, and to the product owner.  I’ve found that other team members always have useful input (hey, area Y of the team needs that too), and the product owner gets to prioritise the refactoring along with other stories.

This also makes plain to all the stakeholders why technical debt is increasing - if too many of these technical stories have been neglected in favour of new features.

Adding a prompt option to Html.Select in ASP.NET MVC

Digging around the source code to the ASP.NET MVC Source Refresh, I discovered a useful extension to the Html.Select helper method.

Say you want a select dropdown with a NULL case, which instructs the user to make a selection.

Eg: You want your first option to be:  ==Select==

To do so, call Html.Select with a htmlAttribute of prompt=”==Select==”

Like:

<%=Html.Select((”Quote.ClientId”), ViewData.Clients, “Name”,”Id”, ViewData.Quote.ClientId,0,false,new {prompt=”==Select==”})%>

alt.vs.team.system

Some thoughts on alternatives to the Visual Studio Team System for building webapps:

• Requirement gathering
  • I like Axure (axure.com) for HTML prototyping ideas, and Visio is okay for architecture diagrams
• Code editing
  • VS Pro + Resharper is pretty good. One of the best “step though debuggers” I’ve used
• Source control
  • Subversion + TortoiseSVN. Any played with Git? Is there a good Git GUI tool?
• Continuous Integration

• Jetbrains TeamCity

• Issue tracking / project website
  • I quite like Trac - wiki, milestones, good SVN integration. Have to maintain Python app though.
• O/R mapper
  • NHibernate? DataSets? LINQtoSQL? What do you use?
• TDD / BDD
  • ASP.NET MVC looks like its going in the right direction; but still early days
  • nUnit / mbUnit / VS built-in? Is there anything that comes close to rSpec in the Rails world for elegance?
  • Mocking frameworks? Moq has a nice syntax - most of the others seem overly complex (record/replay?!)
  • TestRunner? www.gallio.org looks like a good start, but still early days
  • Functional testing? Selenium? WatiN?
  • Continuous Integration server? Is there anything prettier than CruiseControl?
  • Load testing?
• Logging
  • Log4Net>
• Monitoring
  • Current favourite is Webperform
• Support email handing
  • SupportSuite from QualityUnit has a nice Gmail style interface + KB

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