.net - Discrepancy in C# LINQ results -

when this:

currentpage = metadataresponse.applicationtype.pages.find(    page => page.sortorder == ++currentpage.sortorder); 

the value of currentpage null.

but same logic, when assign increment value integer variable, , try currentpage

int sortorder = ++currentpage.sortorder; currentpage = metadataresponse.applicationtype.pages.find(     page => page.sortorder == sortorder); 

currentpage gets populated.

does have answer why 1 works , other doesn't?

note: assume find method applied collection of values.

in first code example, incrementing currentpage each element in collection (this happening because lambda expressions introduce closures on variables captured outer scope - see below code block more info that). in second code example, currentpage incremented once. take how following program behaves:

class program {     static void main(string[] args)     {         func1();         console.writeline("\n");         func2();          console.readkey();     }      private static void func1()     {         int = 0;         var list = new list<int> { 1, 2, 3 };         list.foreach(x => console.writeline(++i));     }      private static void func2()     {         int = 0;         int j = ++i;         var list = new list<int> { 1, 2, 3 };         list.foreach(x => console.writeline(j));     } } 

here more info closures in lambda expressions. have fun! ;-)