Question

I was reading through a .NET 2.0 book and came across this sample code which gets the applications assembly description :

static void Main(string[] args)
{
    Assembly assembly = Assembly.GetExecutingAssembly();
    object[] attributes = 
        assembly.GetCustomAttributes(typeof(AssemblyDescriptionAttribute), false);
    if (attributes.Length > 0)
    {
        AssemblyDescriptionAttribute descriptionAttribute =
            (AssemblyDescriptionAttribute)attributes[0];
        Console.WriteLine(descriptionAttribute.Description);
    }
    Console.ReadKey();
}

It’s quite a lot of code to simply get the assembly description and I would like to know if there’s a simpler way of doing this in .NET 3.5+ using LINQ or lambda expressions?

Answer 1

There isn’t, really. You can make it a bit ‘more fluent’ like this:

 var descriptionAttribute = assembly
         .GetCustomAttributes(typeof(AssemblyDescriptionAttribute), false)
         .OfType<AssemblyDescriptionAttribute>()
         .FirstOrDefault();

 if (descriptionAttribute != null) 
     Console.WriteLine(descriptionAttribute.Description);

[EDIT changed Assembly to ICustomAttributeProvider, cf. answer by Simon Svensson)

And if you need this kind of code a lot, make an extension method on ICustomAttributeProvider:

 public static T GetAttribute<T>(this ICustomAttributeProvider assembly, bool inherit = false) 
 where T : Attribute 
 {
     return assembly
         .GetCustomAttributes(typeof(T), inherit)
         .OfType<T>()
         .FirstOrDefault();
}

Since .Net 4.5, as Yuriy explained, an extension method is available in the framework:

var descriptionAttribute = 
    assembly.GetCustomAttribute<AssemblyDescriptionAttribute>();