CCNA, CCNP, MCSA, CCNA Final Exam, All Answer Test Module With 100/100

When using lambda expressions or anonymous methods in C#, we have to be wary of the access to modified closure pitfall. For example:

How can you enumerate a enum in C#? e.g. the following does not compile:

Today I needed a simple algorithm for checking if a number is a power of 2.

Which C#/.NET Dependency Injection frameworks are worth looking into? And what can you say about their complexity and speed.

I have a project in which I'd like to use some of the .NET 4.0 features but a core requirement is that I can use the System.Data.SQLite framework which is compiled against 2.X. I see mention of this being possible such as the accepted answer here but I don't see how to actually achieve this.

Is there a free or open source library to read Excel files (.xls) directly from a C# program?

This question arose when writing my answer to this one , which talks about the associativity of the null-coalescing operator .

How do I convert a string to a byte array in .NET (C#)?

This question is similar to this one , but focused on C# and .NET.

Given the following class public class Foo { public int FooId { get; set; } public string FooName { get; set; } public override bool Equals(object obj) { Foo fooItem = obj as Foo; return fooItem.FooId == this.FooId; } public override int GetHashCode() { // Which is preferred? return base.GetHashCode(); //return this.FooId.GetHashCode(); } }

In development blogs, online code examples and (recently) even a book, I keep stumbling about code like this:

I am looking for a liberally licensed (MIT, X11, Apache, etc) version of the XMPP protocol for .NET and Mono.

What is the difference between const and readonly and do you use one over the other?

In most of programming languages, we preferred using a dictionary over a hashtable . What are the reasons behind it?

I am looking at the MvcContrib Grid component and I'm fascinated, yet at the same time repulsed, by a syntactic trick used in the Grid syntax :

The following code gives different output when running the release inside Visual Studio, and running the release outside Visual Studio. I'm using Visual Studio 2008 and targeting .NET 3.5. I've also tried .NET 3.5 SP1.

What is the difference between Decimal , Float and Double in C#?

Given that strings are immutable in .NET, I'm wondering why they have been designed such that string.Substring() takes O( substring.Length ) time, instead of O(1)?

How do you give a C# Auto-Property a default value? I either use the constructor, or revert to the old syntax.

I'm getting a warning from ReSharper about a call to a virtual member from my objects constructor. Why would this be something not to do?