Some time ago I have posted an article about using Build Provider feature of ASP.NET 2.0 to build a strongly typed classes for accessing the files found in the application virtual directory. I myself have been using this provider ever since for every Response.Redirect(). I hope that it serves you as well.

I have found yet two more ways of using the Build Providers to make your applications safer (the second one I will describe in few days). Today I present to you, the ClassPropertiesBuildProvider. This time we get a strongly typed way to access name of the properties of our objects. When this could be usefull? Of course everywhere where we have to specify the name of the properties using a plain string. And where could that be? Mostly in data-binding expressions such as Eval and Bind.

Take for example a sample data-binding scenario where we bind a GridView control to an array of Client objects. Each client has Age, FirstName and LastName:

As you can see we get the full intellsense over available properties. Keep in mind that those properties actually return a string containing the name of the property - exact thing needed to use the Eval or Bind. Notice also that in case some property changes its name, or is deleted, we get an instant compile time error as oposite to the runtime exception you get when you use a not strongly typed Eval("Age").

Using the ClassPropertiesBuildProvider is similiar to the PathsBuildProvider. Just add extension=".cpbp" type="ClassPropertiesBuildProvider.ClassPropertiesBuildProvider" to a web.config file and put one or more file with .cpbp extension in the App_Code directory. In this file the first line declares a namespace under which the classes will be generated ("Classes" in this example). On the following line put the name of the assemblies you would like to have analyzed.

The solution is available as a source and binary here: ClassPropertiesBuildProvider.zip (57,43 KB).

As with PathsBuildProvider, the provided solution is for demonstration purposes and as such you should be aware that it might not always work as expected. If you find some bugs, or wish to provide some improvements, please feel free to do it, and contact me so I too can benefit from it

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