2023年4月7日 · A nullable value type T? represents all values of its underlying value type T and an additional null value. For example, you can assign any of the following three values to a bool? variable: true, false, or null. An underlying value type T cannot be a nullable value type itself.

2024年4月24日 · @Nullable 注解可以标注在方法、字段、参数之上，表示对应的值可以为空； @Nullable 注解可以使用在 方法、属性、参数 上，分别表示 方法返回值可以为空、属性值可以为空、参数值可以为空 。 如果可以传入 NULL 值，则标记为 @Nullable，如果不可以，则标注为 ...

Nullable types are a feature of some programming languages which allow a value to be set to the special value NULL instead of the usual possible values of the data type.

2023年4月6日 · 如果要使用基础值类型的默认值来替代 null，请使用 Nullable<T>.GetValueOrDefault() 方法。 还可以将可为空的值类型显式强制转换为不可为 null 的类型，如以下示例所示： int? n = null; //int m1 = n; // Doesn't compile int n2 = (int)n; // Compiles, but throws an exception if n is null

2024年12月14日 · Nullable reference types are a group of features that minimize the likelihood that your code causes the runtime to throw System.NullReferenceException. Three features that help you avoid these exceptions, including the ability to …

C# 提供了一个特殊的数据类型，nullable 类型（可空类型），可空类型可以表示其基础值类型正常范围内的值，再加上一个 null 值。 例如，Nullable< Int32 >，读作"可空的 Int32"，可以被赋值为 -2,147,483,648 到 2,147,483,647 之间的任意值，也可以被赋值为 null 值。

2021年11月16日 · C# nullable 按照修饰变量类型不同, 分成两种情况: 1. nullable value type, 照常理来讲, value 类型的变量不能设为null, 在C# 2.0为了方便程序员使用基础类型变量来存储DB null值, 为value type引入的 nullable 特性, 比如

2019年11月27日 · Probably the most impactful feature of C# 8.0 is Nullable Reference Types (NRTs). It lets you make the flow of nulls explicit in your code, and warns you when you don’t act according to intent. The NRT feature holds you to a higher standard on how you deal with nulls, and as such it issues new warnings on existing code.

2020年11月5日 · The Nullable type allows you to assign a null value to a variable. Nullable types introduced in C#2.0 can only work with Value Type, not with Reference Type. The nullable types for Reference Type is introduced later in C# 8.0 in 2019 so that we can explicitly define if a reference type can or can not hold a null value.

2024年12月4日 · Nullable reference types are available in code that's in a nullable aware context. Nullable reference types, the null static analysis warnings, and the null-forgiving operator are optional language features. All are turned off by default. A nullable context is controlled at the project level using build settings, or in code using pragmas.