C# 中的双问号等号 (??=) 是什么？

Question

我经常看到这样的陈述：

int? a = 5;

//...other code

a ??= 10;

第二行的??=是什么意思？我以前见过 ?? 用于空合并，但我从未见过它与等号一起使用。

Answer 1

同理：

if (a == null) {
  a = 10;
}

这是 C# 8.0 中引入的运算符：https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/operators/null-coalescing-operator

Available in C# 8.0 and later, the null-coalescing assignment operator ??= assigns the value of its right-hand operand to its left-hand operand only if the left-hand operand evaluates to null. The ??= operator doesn't evaluate its right-hand operand if the left-hand operand evaluates to non-null.

C# 中的双问号等号 (??=) 是什么？

What is the double question mark equals sign (??=) in C#?

c#

conditional-operator

equals-operator