preserving Array elements using c#.net

Consider the two arrays:
        string[] str = new string[1];
            str[0] = "str";
            string[] str1 = new string[2];
            str1[0] = "str1";
            str1[1] = "str2";

To append an two arraycollections:
str = str.Concat(str1).ToArray(); //the  result was stored in the str array. this will work only in .net 2008

To add new element in the array:
        Array.Resize(ref str, newSize);
            str[newSize-1] = "newvalue";

Convert string to datatime format

1.

string str = "24/10/2008";
 DateTime dt = DateTime.ParseExact(str, "dd/MM/yyyy", 
                                   Thread.CurrentThread.CurrentCulture);
 
2. 
DateTime date = System.DateTime.ParseExact(str, "dd/MM/yyyy", null);
 DateTime date = System.DateTime.ParseExact(str, "HH:mm:ss", null);
 

Effect of Double in .net

Did u feel its a best way to use double in your application.

Test the following scenario:
double a=0.3;
double b=0.1+0.1+0.1;(or)0.2+0.1;
if(a==b)
  MessageBox.Show(r u great?);
else
  MessageBox.Show(u r great!);

if u put float u wont get the  same output.


There is not only problem in using this format. but there are lot of issues and doubt  while using double datatype. So consider twice before using double in your application
Solution: We cant say it as an error. in Java also the same thing will happen. its some double precision format.
Better using decimal is a good solution.

Linq for XML .net 2008

Language integrated query for xml
Its very similar to .net 2005 xml processing. the feature added here in .net 2008 is linq.
We can query into the xml elements directly like sql queries.
Also we do the same task with easy and less line of codes(loc) using linq. We can also write events for nodes so any triger on the node are watchable. 


For more and through ref search : http://msdn.microsoft.com/en-us/library/bb308960.aspx

System.Windows.Forms.Timer vs. System.Threading.Timer vs. System.Timers.Timer

Feature description	System.Timers.Timer	System.Threading.Timer	System.Windows.Forms.Timer
Support for adding and removing listeners after the timer is instantiated.	Yes	No	Yes
Supports call backs on the user-interface thread	Yes	No	Yes
Calls back from threads obtained from the thread pool	Yes	Yes	No
Supports drag-and-drop in the Windows Forms Designer	Yes	No	Yes
Suitable for running in a server multi-threaded environment	Yes	Yes	No
Includes support for passing arbitrary state from the timer initialization to the callback.	No	Yes	No
Implements IDisposable	Yes	Yes	Yes
Supports one-off callbacks as well as periodic repeating callbacks	Yes	Yes	Yes
Accessible across application domain boundaries	Yes	Yes	Yes
Supports IComponent – hostable in an IContainer	Yes	No	Yes

Using the System.Windows.Forms.Timer is a relatively obvious choice for user interface programming.  Choosing between the other two options is less obvious and generally the choice between the two is insignificant.  If hosting within an IContainer is necessary then obviously System.Timers.Timer is the right choice.  However, if no specific System.Timers.Timer feature is required, then I suggest choosing System.Threading.Timer by default, simply because it is a slightly lighter weight implementation.