What the use of ?? symble

Hi,

=> lambda operator, read as "goes to"
?? null-coalescing operator, this is used to define a default value in the case of nullable value type or reference type
+= addition assignment operator. this is equal to x=x+1

Check for this link http://msdn.microsoft.com/en-us/library/sa7629ew.aspx more details

Blessy Baby
Digitalmesh Softech pvt Ltd
https://blessybaby.wordpress.com/

pl check out below the link in my blog for your queries explanation .

http://silverlightpractice.blogspot.com/2011/12/how-to-do-work-with-and-in-c-40.html