Project Natal - Touch free HID

Wow i have never been so excited about a new HID since the announcement of the EmoticEpoch. If you havent read about this new XBox360 centered offering, its time! If you are an XNA platform developer, you are probably foaming at the mouth by now :P

Check it out

Microsoft .NET Framework Application Development Foundation Training Kit - Chapter 1 - 'Rich' Notes

This is the first of many posts to come to aid in reviewing what i have learned from the Training Kit prior to taking the MCTS Exam 70-536.

Structs vs Classes

Custom Operators (==, + etc.)

Reference vs Value Types

Nullable Types (can only be value types)

Generics & Constraints on Generic classes

Events/Delegates
class Program
{
static void Main(string[] args)
{
DelegateTest test = new DelegateTest();
test.OnTimeChangedInstance += new DelegateTest.OnTimeChanged(test_OnTimeChanged);
test.RunTest();
}

private static void test_OnTimeChanged(DateTime d)
{
System.Diagnostics.Debug.WriteLine(d.ToLongTimeString());
}
}
class DelegateTest
{
public delegate void OnTimeChanged(DateTime newTime);
public OnTimeChanged OnTimeChangedInstance;

public void RunTest()
{
if (OnTimeChangedInstance != null)
OnTimeChangedInstance(DateTime.Now);
}
}

Type Forwarding
Allows you to move a type from assembly X into assembly Y for an application that is currently deployed and only has knowledge of assembly X without having to recompile the application. In assembly Y you create the type as it was in assembly X. Then in assembly X you remove the type that was moved to Y and replace it with an Assembly attribute that specifies the new location of the moved type. E.g. move type Car from assembly X to Y would result in assembly X no longer containing type Car, Assembly Y now containing Type Car and Assembly X adding the attribute [assembly:typeforwardedto(typeof(Y.Car))].http://www.xhydra.com/mcts-70-536/type-forwarding.html

Conversion Between Types
• System.Convert – converts between types that implement System.IConvertible.
• Cast operator – (int) obj.
• Type.Parse, Type.ToString
• Type.TryParse, Type.TryParseExact.
• Narrowing/Widening Conversions – Narrowing Conversions occur when the range or precision of the source type exceeds that of the destination type.

How to Implement Conversion in Custom Types
• Define conversion operators to simplify narrowing (explicit in c#) and widening (implicit in c#) conversions between numeric types.
• Override ToString to provide conversion to strings, override Parse to provide conversion from strings.
• Implement System.IConvertible to enable conversion though System.Convert. The interface has ~ 17 methods to implement – ToBoolean() etc.

Boxing/Unboxing
• Is the conversion between reference and value types.
• Should be avoided due to overhead
• All struct’s you create inherit from system.object which exposes the ToString method. Why would you want to override the ToString method in a struct? Avoids boxing the custom struct (value type) to the object type (reference type) in order to call ToString.