Enum To Collection: Make Binding Easy

I prefer storing domain data for applications in an Enum, when that data seldom/rarely changes. In doing so, I find that I need to display this data in the form of a DropDownList in the UI. Through a generic "Enum To Collection" method, and the use of ObjectDataSources, this task is very easy.

Here is the generic static method to turn an Enum into a Collection:

public static Collection<KeyValuePair<string, int>> ToCollection<T>()



{



      Collection<KeyValuePair<string, int>> collection = new Collection<KeyValuePair<string, int>>();







      Array values = Enum.GetValues(typeof (T));







      foreach (int value in values)



      {



           collection.Add(new KeyValuePair<string, int>(Enum.GetName(typeof (T), value), value));



      }







      return collection;



}

I then define a static method in my business class decorated with the DataObject attribute:

[DataObjectMethod(DataObjectMethodType.Select)]



public static Collection<KeyValuePair<string, int>> GetDays()



{



     return EnumHelper.ToCollection<Days>();



}

Then, just drop a DropDownList control onto your page. Use the Configure Data Source wizard to select your static method you just defined:

And that's it. Check it out:

Note: I like to set "AppendDataBoundItems" to true, and add my "-Select-" value on the page. This is nice because I don't have to deal with that logic in my business tier.

Hope you like it and happy binding.

Easy trick to decreasing your page size!

While working on a project with Than Nap, a fellow Slalom consultant, I picked up a simple trick to decreasing your page size.

If you have worked with MasterPages in ASP.NET 2.0, you have no doubt been looking at the source of a page, and seen something like the following....





The naming convention of controls following the hierarchy of pages in which the control is nested. When the ID of a masterpage is not explicitly set, it defaults to ctl00. When you add a new MasterPage to a project/website, you get default content like the following...



If you just start going from here, you may be making a mistake. The names you give (or don't give) your MasterPage and ContentPlaceHolders show up twice per control. And you might be appalled if you look at the source for a gridview/detailsview.

Here's the tip:

1. Name your contentplaceholders with as short of name as possible. I use "c" for a main content area, "t" for a title, and so on.


2. Add the following piece of code to code behind of your MasterPage.

The same example I started with (btnSave) would now look like this in source...

In larger applications, with complex web forms, this little trick may get you a 10% decrease in page size alone!