I've further elaborated the idea above, using an extension method:

// Base interfaces for a node
public interface INode
where T : INode // A child is the same class as the parent
{
Guid Id { get; set; }
List Children { get; set; }
}

// Static class containing Extension Methods
public static class NodeExtensions
{
// Recursively removes a node by its id
public static void Remove(this INode node, Guid id)
where T : INode
{
// List that will contains the nodes to be removed
// Can't remove nodes directly in the foreach loop
// (will throw "Collection was modified; enumeration operation may not execute.")
List toRemove = new List();

    if (node.Children == null)
        return; // No childrens, exit

    foreach (var child in node.Children)
    {
        if (child.Id == id)
            toRemove.Add(child); // The node has to be removed
        else
            child.Remove(id); // Recursion here
    }

    // Removes all found nodes
    foreach (var child in toRemove)
        node.Children.Remove(child);
}

}

You could also use the short date format specifier:

ToString("d")

Remember when I told you to use int level = book.Select("ancestor::Entity").Count to get the level of a node? What ancestor::Entity does is returning the list of all the ancestor Entity nodes, you just have to avoid using Count. If you need the token value, you just have to subsequently select Token, like this: ancestor::Entity/Token. To understand what you can do with XPath, I strongly suggest you to read here.

Here you go:

var query = from item in A.Union(B)
group item by item.Name into grp
select new { Name = grp.Key, N = grp.Sum(t => t.N) };

modified on Wednesday, July 20, 2011 10:46 AM

For the parent, it seems you are selecting a not-leaf node (I'd say an 'Entity' node), so, using value, you are getting the full content of that node, all descendants included. If you want a string value, you must select a Token or a Description. For the level, I forgot you can't use scalar function in XPath when selecting nodes. You can simply use Select and then Count the result: int level = book.Select("ancestor::Entity").Count;

For the parent node, you can use .. to navigate upward the xml tree (like as it where a directory). Using your Example, string parent = book.SelectSingleNode("../Token").Value; will get you the parent token of the current entity. For the depth, you could try to count the number of entity parent nodes, like this: string level = book.SelectSingleNode("count(ancestor::Entity)").Value; I don't know if that will give you a 0-based or a 1-based value, you will have to do some tests.

Use // to search in any level into your XML. The following XPath will give you what you want: //Entity[contains(./Description, 'Company')]/Token

Here for a complete tutorial.

This is what wikipedia says about Order of Operations: There exist differing conventions concerning the unary operator - (usually read "minus"). In written or printed mathematics, the expression -3² is interpreted to mean -(3²) = -9, but in some applications and programming languages, notably the application Microsoft Office Excel and the programming language bc, unary operators have a higher priority than binary operators, that is, the unary minus (negation) has higher precedence than exponentiation, so in those languages -3² will be interpreted as (-3)² = 9. [1] In any case where there is a possibility that the notation might be misinterpreted, it is advisable to use brackets to clarify which interpretation is intended.

modified on Friday, June 3, 2011 8:56 AM

Actually, Google is right. sqrt(-1^2) = sqrt(-(1^2)) = sqrt(-1*1) = sqrt(-1) = i sqrt(-i^2) = sqrt(-(i^2)) = sqrt(-1*-1) = sqrt(1) = 1

I said that at the end of my post. I agree you are losing many advatages of polymorphism, but, at least, you can reuse the Create login in multple classes.

You can use generics like this:

abstract class b<T> where T: b, new()
{
...
public T Create() { return new T(); }
}

class D1 : b<D1>
{
...
}
class D2 : b<D2>
{
...
}

So, you can do:

D1 myClassD1 = new D1();
D1 newClassD1 = D1.Create();

But, you can't do anymore:

b myClassAb = new D1;
D1 newClassAb = myClassAb.Create();

because you'd have to specify the generic type for class b.

You have to play a bit with interfaces. Look here for a sample.

Don't worry too much about that, it's only a warning. If a non-static method don't use any instance-level method or property, FxCop tells you that there are no reasons that method should not be static, and suggest you to make it static. But, if that method is part of an interface implementation (or exposed publicly and alraedy used from other methods), there ARE reasons that should not be static, so you should ignore the warning. If you want, you can use the SuppressMessage attribute to avoid getting the warning for specific methods.

Since it seems you are already using .NET 4, you can give a look to the new Thread-safe collections.

After a quick search I found this Often people try to code complex soluting when the OS already give them the option...

You are missing System.Diagnostics.Process.Start(shutDownBlocker);

Talking about efficiency, I read somewere on MSDN that, for generating a list of unique elements, the more efficient way is to use an HashSet (as PIEBALDconsult already said) instead of the Distinct extension method. Something like this:

var query = string.Join(",", arr) // join to make one string
.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries) // split to array
.Select(t => t.Trim()); // trim each entry

var set = new Hashset<string>

foreach (string item in query)
set.Add(item); // add items to the hash set, this ensure unique

string[] vals = set.ToArray(); // back to array

You said "I have now developed a simple console app based on the example". So I thought that you had put the WCF service on a separate Console Application. If you have already put the WCF service into the Windows service, you should be able to browse it from IE on the url you specified when coding it (the example I gave you uses http://localhost:8080/hello). You have only to add a service reference to your WCF service in the Silverlight application so that it can communicate with the Windows service.

Now you have a Windows service (that is actually a console application) that manages your queue, and a console application that exposes a WCF service. What you have to do is to put the two things together: include the code of the new console app into the code of your Window Service and make sure that both reference the same queue instance. Then, when you start the Windows service, it will also expose the WCF service that you can call from Silverlight.