C# 中的 ContainsKey
csharpprogrammingserver side programming更新于 2025/10/8 3:32:00
ContainsKey 是 C# 中的 Dictionary 方法，用于检查 Dictionary 中是否存在某个键。
声明一个 Dictionary 并添加元素 −
var dict = new Dictionary<string, int>() {
{"TV", 1},
{"Home Theatre", 2},
{"Amazon Alexa", 3},
{"Google Home", 5},
{"Laptop", 5},
{"Bluetooth Speaker", 6}
};
现在，假设您需要检查字典中是否存在某个特定元素。为此，请使用 ContainsKey() 方法 −
if (dict.ContainsKey("Laptop") == true) {
Console.WriteLine(dict["Laptop"]);
}
以下是代码 −
示例
using System;
using System.Collections.Generic;
public class Demo {
public static void Main() {
var dict = new Dictionary<string, int>() {
{"TV", 1},
{"Home Theatre", 2},
{"Amazon Alexa", 3},
{"Google Home", 5},
{"Laptop", 5},
{"Bluetooth Speaker", 6}
};
if (dict.ContainsKey("Laptop") == true) {
Console.WriteLine(dict["Laptop"]);
}
if (dict.ContainsKey("Amazon Alexa") == true) {
Console.WriteLine(dict["Amazon Alexa"]);
}
}
}
输出
5 3
