1.1 KiB
1.1 KiB
title | localeTitle |
---|---|
Single Or Default | 单一或默认 |
的SingleOrDefault
返回满足指定条件的序列中的单个元素,如果未找到任何元素,则返回默认值。如果找到满足指定条件的多个元素,则该方法将抛出异常。
签名
Enumerable.SingleOrDefault<TSource>(IEnumerable<TSource>, Func<TSource, Boolean>)
例
var fruits = new List<Fruit>() {
new Fruit() { Id = 1, Name = "Orange", Color = "Orange", Quantity: 3 },
new Fruit() { Id = 2, Name = "Strawberry", Color = "Red", Quantity: 12 },
new Fruit() { Id = 3, Name = "Grape", Color = "Purple", Quantity: 25 },
new Fruit() { Id = 4, Name = "Pineapple", Color = "Yellow", Quantity: 1 },
new Fruit() { Id = 5, Name = "Apple", Color = "Red", Quantity: 5 },
new Fruit() { Id = 6, Name = "Mango", Color = "Yellow", Quantity: 2 }
};
var purpleFruit = fruits.SingleOrDefault(f => f.Color == "Purple"); // Grape
var greenFruit = fruits.SingleOrDefault(f => f.Color == "Green"); // null