c# - Passing arguments, does unboxing occur -

what have read, passing arguments default valuetypes. in example first function test1 takes reference type , unbox, decrease performance if got right. have never read test2 increase performance.

so whats best practice?

public main(){     string test = "hello";     test1(test); // line perform boxing? it's not performance?     test2(ref test); // passing reference reference }  public string test1(string arg1) {     return arg1; }  public string test2(ref string arg1) {     return arg1; } 

there's no boxing or unboxing involved @ here. string reference type - why boxed? mean?

even if used int instead, there'd no need boxing, because there's no conversion of value actual object.

i suspect understanding of both boxing , parameter passing flawed.

boxing occurs when value type value needs converted object, in order used variable (somewhere) of interface or object type. this boxes:

int value = 10; foo(value);  ...  public void foo(object x) { } 

... wouldn't occur if foo changed such type of x int instead.

the detailed rules on boxing become complicated state precisely , accurately, particularly generics come in, that's basics.