« Parameter modifiers » : différence entre les versions
De Banane Atomic
Aller à la navigationAller à la recherche
(→out) |
|||
| Ligne 26 : | Ligne 26 : | ||
= [https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/method-parameters#ref-readonly-modifier ref readonly] = | = [https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/method-parameters#ref-readonly-modifier ref readonly] = | ||
Pass a parameter by reference and make it readonly. | |||
<kode lang='cs'> | |||
var item = new Item("name"); | |||
Method(ref item); | |||
static void Method(ref readonly Item item) | |||
{ | |||
item = new Item("new name"); // you can't assign a readonly variable | |||
item.Name = "new name"; // you can modify the object properties | |||
} | |||
</kode> | |||
= [https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/method-parameters#out-parameter-modifier out] = | = [https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/method-parameters#out-parameter-modifier out] = | ||
Version du 24 mai 2024 à 15:19
ref
Pass a parameter by reference.
|
// value type
var i = 10;
Method0(i); // 10
Method1(ref i); // 11
void Method0(int i) => i++; // pass the value type parameter by value (copy)
void Method1(ref int i) => i++; // pass the value type parameter by reference
// reference type
var item = new Item("init name");
Method2(item); // init name
Method3(ref item); // new name 3
// pass the reference type parameter by value: the reference is passed by value (copy)
// if the parameter is overwritten (the copy of the reference is overwritten), it doesn't affect the initial object
void Method2(Item item) => item = new("new name 2");
// pass the reference type parameter by reference: the reference is passed by reference
// if the parameter is overwritten (the initial reference is overwritten), it does affect the initial object
void Method3(ref Item item) => item = new("new name 3");
|
ref readonly
Pass a parameter by reference and make it readonly.
|
|
var item = new Item("name");
Method(ref item);
static void Method(ref readonly Item item)
{
item = new Item("new name"); // you can't assign a readonly variable
item.Name = "new name"; // you can modify the object properties
}
|
out
Allow to initialize the parameter in the method.
|
|
Method5(out var j); // 5 void Method5(out int i) => i = 5; |
