C# – Thoughts about using Silverlight In Desktop Apps

There is actually a (subtle) difference between the two. Imagine you have the following code in File1.cs:

// File1.cs
using System;
namespace Outer.Inner
{
    class Foo
    {
        static void Bar()
        {
            double d = Math.PI;
        }
    }
}

Now imagine that someone adds another file (File2.cs) to the project that looks like this:

// File2.cs
namespace Outer
{
    class Math
    {
    }
}

The compiler searches Outer before looking at those using directives outside the namespace, so it finds Outer.Math instead of System.Math. Unfortunately (or perhaps fortunately?), Outer.Math has no PI member, so File1 is now broken.

This changes if you put the using inside your namespace declaration, as follows:

// File1b.cs
namespace Outer.Inner
{
    using System;
    class Foo
    {
        static void Bar()
        {
            double d = Math.PI;
        }
    }
}

Now the compiler searches System before searching Outer, finds System.Math, and all is well.

Some would argue that Math might be a bad name for a user-defined class, since there's already one in System; the point here is just that there is a difference, and it affects the maintainability of your code.

It's also interesting to note what happens if Foo is in namespace Outer, rather than Outer.Inner. In that case, adding Outer.Math in File2 breaks File1 regardless of where the using goes. This implies that the compiler searches the innermost enclosing namespace before it looks at any using directive.

No -- Silverlight 3 does not support printing natively.

You can usually get some things done in the browser using Javascript, but that won't let you directly send a PDF the way you're discribing.

It's possible to write a seperate app that lives on the client machine and then integrate with that... For an internal line-of-business app that could be a good solution, but the obvious drawback is that you're stepping outside of Silverlight's multi-platform bubble.

Here's an article that might be worth looking at: http://jonas.follesoe.no/PrintingInSilverlight2UsingCSSAndASPNETAJAX4.aspx (the comments are also interesting, and some of them talk about working with PDFs)

Update: Silverlight 4 now supports this.