c# - Unable to update the contents of a Generic List -

i have simple class has boolean field:

public struct foo { bool isavailable; } 

now have list of foos:

list < foo >  list = new list< foo >(); 

later on enumerate each foo in list , try update isavailable field:

foreach(foo foo in list) {     foo.isavailable = true;  } 

but above code never updates list. doing wrong here , what's remedy.

it's because foo mutable struct.

when fetch value list, it's making copy - because that's how value types behave. you're changing copy, leaving original value unchanged.

suggestions:

• you should using class
• don't create mutable structs. behave in ways can hard predict, or @ least not way might expect when you're not explicitly thinking it.

while could change code iterate on list in different way , replace value each time, it's bad idea so. use class... or project list new list appropriate values.

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original answer, when foo class

it should work fine. example, here's short complete program does work:

using system.collections.generic;  public class foo {     public bool isavailable { get; set; }     public string name { get; set; }      public override string tostring()     {         return name + ": " + isavailable;     } }  class test {     static void main()     {         list<foo> list = new list<foo>()         {             new foo { name = "first", isavailable = true },             new foo { name = "second", isavailable = false },             new foo { name = "third", isavailable = false },         };          console.writeline("before:");         list.foreach(console.writeline);         console.writeline();          foreach (foo foo in list)         {             foo.isavailable = true;         }          console.writeline("after:");         list.foreach(console.writeline);     } } 

try adapt current code similar short complete program doesn't work, post that, , can work out what's going on.