{"id":307066,"date":"2024-05-20T20:26:12","date_gmt":"2024-05-20T12:26:12","guid":{"rendered":""},"modified":"2024-05-20T20:26:25","modified_gmt":"2024-05-20T12:26:25","slug":"%e5%9c%a8c%e4%b8%8b%e6%9c%89%e4%bb%80%e4%b9%88%e5%a5%bd%e5%8a%9e%e6%b3%95%e5%8f%af%e4%bb%a5%e6%9b%bf%e4%bb%a3if-else%e5%92%8cswitch-case","status":"publish","type":"post","link":"https:\/\/docs.pingcode.com\/ask\/307066.html","title":{"rendered":"\u5728C#\u4e0b\u6709\u4ec0\u4e48\u597d\u529e\u6cd5\u53ef\u4ee5\u66ff\u4ee3if-else\u548cswitch-case"},"content":{"rendered":"

\"\u5728C#\u4e0b\u6709\u4ec0\u4e48\u597d\u529e\u6cd5\u53ef\u4ee5\u66ff\u4ee3if-else\u548cswitch-case\"<\/p>\n

\u5728C#\u4e0b\uff0c\u53ef\u4ee5\u7528\u591a\u6001\u3001\u7b56\u7565\u6a21\u5f0f\u3001\u59d4\u6258\u3001\u8868\u9a71\u52a8\u65b9\u6cd5\u3001\u6a21\u5f0f\u5339\u914d<\/strong>\u6765\u66ff\u4ee3if-else\u548cswitch-case\u3002\u591a\u6001\u6027<\/strong>\u662f\u9762\u5411\u5bf9\u8c61\u7f16\u7a0b\u4e2d\u7684\u4e00\u4e2a\u6838\u5fc3\u6982\u5ff5\uff0c\u5b83\u5141\u8bb8\u6211\u4eec\u901a\u8fc7\u57fa\u7c7b\u7684\u63a5\u53e3\u6765\u8c03\u7528\u6d3e\u751f\u7c7b\u7684\u65b9\u6cd5\u3002\u8fd9\u6837\u505a\u7684\u597d\u5904\u662f\uff0c\u6211\u4eec\u53ef\u4ee5\u8bbe\u8ba1\u51fa\u66f4\u52a0\u7075\u6d3b\u548c\u53ef\u6269\u5c55\u7684\u7cfb\u7edf\u3002\u4ee5\u7b56\u7565\u6a21\u5f0f\u4e3a\u4f8b\uff0c\u5b83\u5141\u8bb8\u5728\u8fd0\u884c\u65f6\u9009\u62e9\u6700\u9002\u5408\u7684\u7b97\u6cd5\u3002\u901a\u8fc7\u5b9a\u4e49\u4e00\u7cfb\u5217\u7684\u7b97\u6cd5\uff0c\u5e76\u628a\u5b83\u4eec\u5c01\u88c5\u5728\u72ec\u7acb\u7684\u7b56\u7565\u7c7b\u4e2d\uff0c\u53ef\u4ee5\u5728\u8fd0\u884c\u65f6\u51b3\u5b9a\u4f7f\u7528\u54ea\u4e2a\u7b97\u6cd5\uff0c\u8fd9\u79cd\u65b9\u5f0f\u53ef\u4ee5\u907f\u514d\u4f7f\u7528\u591a\u91cd\u6761\u4ef6\u8f6c\u79fb\u8bed\u53e5\uff0c\u63d0\u9ad8\u4ee3\u7801\u7684\u53ef\u7ef4\u62a4\u6027\u548c\u6269\u5c55\u6027\u3002<\/p>\n<\/p>\n

\u4e00\u3001\u591a\u6001\u6027<\/h3>\n<\/p>\n

\u5728C#\u4e2d\uff0c\u591a\u6001\u6027\u4f7f\u6211\u4eec\u80fd\u591f\u901a\u8fc7\u57fa\u7c7b\u6216\u8005\u63a5\u53e3\u5f15\u7528\u53d8\u91cf\u6765\u6267\u884c\u6d3e\u751f\u7c7b\u7684\u65b9\u6cd5\uff0c\u8fd9\u4f7f\u5f97\u4ee3\u7801\u66f4\u52a0\u901a\u7528\u548c\u7075\u6d3b\u3002\u4e3e\u4e2a\u4f8b\u5b50\uff1a<\/p>\n<\/p>\n

public abstract class Animal<\/p>\n
{<\/p>\n
    public abstract void Speak();<\/p>\n
}<\/p>\n
public class Dog : Animal<\/p>\n
{<\/p>\n
    public override void Speak()<\/p>\n
    {<\/p>\n
        Console.WriteLine("Bark!");<\/p>\n
    }<\/p>\n
}<\/p>\n
public class Cat : Animal<\/p>\n
{<\/p>\n
    public override void Speak()<\/p>\n
    {<\/p>\n
        Console.WriteLine("Meow!");<\/p>\n
    }<\/p>\n
}<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u7136\u540e\u53ef\u4ee5\u521b\u5efa\u4e00\u4e2aAnimal\u7c7b\u578b\u7684\u5217\u8868\uff0c\u5305\u542bDog\u548cCat\u7684\u5b9e\u4f8b\uff0c\u5e76\u904d\u5386\u8fd9\u4e2a\u5217\u8868\u8ba9\u6bcf\u4e2a\u52a8\u7269\u53d1\u58f0\u3002\u8fd9\u6837\u5c31\u907f\u514d\u4e86\u4f7f\u7528if-else\u6216switch-case\u6765\u786e\u5b9a\u52a8\u7269\u7c7b\u578b\u5e76\u8c03\u7528\u76f8\u5e94\u7684\u65b9\u6cd5\u3002<\/p>\n<\/p>\n
\u4e8c\u3001\u7b56\u7565\u6a21\u5f0f<\/h3>\n<\/p>\n
\u7b56\u7565\u6a21\u5f0f<\/strong>\u5b9a\u4e49\u4e86\u4e00\u7cfb\u5217\u7684\u7b97\u6cd5\uff0c\u5e76\u5c06\u6bcf\u4e2a\u7b97\u6cd5\u5c01\u88c5\u8d77\u6765\uff0c\u4f7f\u5b83\u4eec\u53ef\u4ee5\u4e92\u6362\u3002\u8fd9\u79cd\u6a21\u5f0f\u8ba9\u7b97\u6cd5\u7684\u53d8\u5316\u72ec\u7acb\u4e8e\u4f7f\u7528\u7b97\u6cd5\u7684\u5ba2\u6237\u3002\u4ee5\u4e0b\u662f\u7b56\u7565\u6a21\u5f0f\u7684\u4e00\u4e2a\u793a\u4f8b\uff1a<\/p>\n<\/p>\n
public interface IStrategy<\/p>\n
{<\/p>\n
    void Execute();<\/p>\n
}<\/p>\n
public class ConcreteStrategyA : IStrategy<\/p>\n
{<\/p>\n
    public void Execute()<\/p>\n
    {<\/p>\n
        Console.WriteLine("Strategy A executed.");<\/p>\n
    }<\/p>\n
}<\/p>\n
public class ConcreteStrategyB : IStrategy<\/p>\n
{<\/p>\n
    public void Execute()<\/p>\n
    {<\/p>\n
        Console.WriteLine("Strategy B executed.");<\/p>\n
    }<\/p>\n
}<\/p>\n
public class Context<\/p>\n
{<\/p>\n
    private IStrategy _strategy;<\/p>\n
    public Context(IStrategy strategy)<\/p>\n
    {<\/p>\n
        _strategy = strategy;<\/p>\n
    }<\/p>\n
    public void SetStrategy(IStrategy strategy)<\/p>\n
    {<\/p>\n
        _strategy = strategy;<\/p>\n
    }<\/p>\n
    public void ExecuteStrategy()<\/p>\n
    {<\/p>\n
        _strategy.Execute();<\/p>\n
    }<\/p>\n
}<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u5ba2\u6237\u53ef\u4ee5\u6839\u636e\u9700\u8981\u66f4\u6539\u4e0a\u4e0b\u6587\u4e2d\u4f7f\u7528\u7684\u7b56\u7565\uff0c\u8fd9\u6837\u5c31\u4e0d\u9700\u8981if-else\u6216switch-case\u6765\u51b3\u5b9a\u4f7f\u7528\u54ea\u79cd\u7b97\u6cd5\u3002<\/p>\n<\/p>\n
\u4e09\u3001\u59d4\u6258<\/h3>\n<\/p>\n
\u59d4\u6258\u662fC#\u7684\u4e00\u79cd\u7c7b\u578b\uff0c\u5b83\u63d0\u4f9b\u4e86\u4e00\u79cd\u5c06\u65b9\u6cd5\u4f5c\u4e3a\u53c2\u6570\u4f20\u9012\u7684\u80fd\u529b\u3002\u59d4\u6258\u53ef\u4ee5\u7528\u6765\u66ff\u4ee3if-else\u548cswitch-case\u7ed3\u6784\uff0c\u5c24\u5176\u662f\u5728\u4e8b\u4ef6\u9a71\u52a8\u7684\u7a0b\u5e8f\u8bbe\u8ba1\u6216\u56de\u8c03\u65b9\u6cd5\u7684\u65f6\u5019\u3002\u4e0b\u9762\u662f\u4e00\u4e2a\u4f7f\u7528\u59d4\u6258\u6765\u66ff\u4ee3\u6761\u4ef6\u8bed\u53e5\u7684\u7b80\u5355\u4f8b\u5b50\uff1a<\/p>\n<\/p>\n
public delegate void Operation(int x, int y);<\/p>\n
public class Calculator<\/p>\n
{<\/p>\n
    public void Add(int x, int y)<\/p>\n
    {<\/p>\n
        Console.WriteLine(x + y);<\/p>\n
    }<\/p>\n
    public void Subtract(int x, int y)<\/p>\n
    {<\/p>\n
        Console.WriteLine(x - y);<\/p>\n
    }<\/p>\n
}<\/p>\n
public class Program<\/p>\n
{<\/p>\n
    public static void PerformOperation(Operation operation, int x, int y)<\/p>\n
    {<\/p>\n
        operation?.Invoke(x, y);<\/p>\n
    }<\/p>\n
    public static void MAI<\/a>n()<\/p>\n
    {<\/p>\n
        Calculator calc = new Calculator();<\/p>\n
        Operation addOperation = new Operation(calc.Add);<\/p>\n
        Operation subtractOperation = new Operation(calc.Subtract);<\/p>\n
        PerformOperation(addOperation, 5, 3);<\/p>\n
        PerformOperation(subtractOperation, 5, 3);<\/p>\n
    }<\/p>\n
}<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u5728\u8fd9\u4e2a\u4f8b\u5b50\u4e2d\uff0c\u6211\u4eec\u5b9a\u4e49\u4e86\u4e00\u4e2aOperation\u7c7b\u578b\u7684\u59d4\u6258\uff0c\u5e76\u4e14Calculator\u7c7b\u6709\u4e24\u4e2a\u65b9\u6cd5Add\u548cSubtract\uff0c\u5b83\u4eec\u7684\u7b7e\u540d\u4e0eOperation\u59d4\u6258\u5339\u914d\u3002\u5728Main\u65b9\u6cd5\u4e2d\uff0c\u6211\u4eec\u521b\u5efa\u4e86\u59d4\u6258\u5b9e\u4f8b\uff0c\u5e76\u8c03\u7528PerformOperation\u65b9\u6cd5\uff0c\u4ece\u800c\u907f\u514d\u4e86\u4f7f\u7528\u6761\u4ef6\u8bed\u53e5\u3002<\/p>\n<\/p>\n
\u56db\u3001\u8868\u9a71\u52a8\u65b9\u6cd5<\/h3>\n<\/p>\n
\u8868\u9a71\u52a8\u65b9\u6cd5\u662f\u53e6\u4e00\u79cd\u6d88\u9664\u590d\u6742\u6761\u4ef6\u8bed\u53e5\u7684\u6280\u672f\u3002\u6b64\u65b9\u6cd5\u901a\u8fc7\u6570\u636e\u7ed3\u6784\uff08\u5982\u6570\u7ec4\u3001\u5b57\u5178\u7b49\uff09\u6765\u6620\u5c04\u6761\u4ef6\u548c\u7b56\u7565\u7684\u5173\u7cfb\u3002\u4e0b\u9762\u662f\u4e00\u4e2a\u7b80\u5355\u7684\u4f8b\u5b50\uff1a<\/p>\n<\/p>\n
Dictionary<string, Action> operations = new Dictionary<string, Action><\/p>\n
{<\/p>\n
    { "create", () => Console.WriteLine("Creating item...") },<\/p>\n
    { "delete", () => Console.WriteLine("Deleting item...") }<\/p>\n
};<\/p>\n
string command = Console.ReadLine();<\/p>\n
if(operations.TryGetValue(command, out Action action))<\/p>\n
{<\/p>\n
    action.Invoke();<\/p>\n
}<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u5728\u8fd9\u91cc\uff0c\u6211\u4eec\u521b\u5efa\u4e86\u4e00\u4e2a\u64cd\u4f5c\u5b57\u7b26\u4e32\u5230\u884c\u4e3a\u7684\u6620\u5c04\u3002\u800c\u4e0d\u662f\u4f7f\u7528\u4e00\u4e2a\u957f\u957f\u7684if-else\u6216switch-case\uff0c\u6211\u4eec\u7b80\u5355\u5730\u4ece\u5b57\u5178\u4e2d\u68c0\u7d22\u5e76\u6267\u884c\u5bf9\u5e94\u7684\u884c\u4e3a\u3002<\/p>\n<\/p>\n
\u4e94\u3001\u6a21\u5f0f\u5339\u914d<\/h3>\n<\/p>\n
C# 7.0 \u5f15\u5165\u4e86\u6a21\u5f0f\u5339\u914d<\/strong>\u7279\u6027\uff0c\u8fd9\u662f\u5bf9switch-case\u7684\u5f3a\u5316\u3002\u5b83\u4e0d\u4ec5\u53ef\u4ee5\u6309\u7167\u503c\u5339\u914d\uff0c\u8fd8\u53ef\u4ee5\u6309\u7167\u7c7b\u578b\u5339\u914d\u548c\u66f4\u590d\u6742\u7684\u6570\u636e\u7ed3\u6784\u3002\u4ee5\u4e0b\u4f7f\u7528\u6a21\u5f0f\u5339\u914d\u7684\u4f8b\u5b50\u6f14\u793a\u4e86\u5982\u4f55\u66ff\u4ee3switch-case\uff1a<\/p>\n<\/p>\n
public void DoWork(object item)<\/p>\n
{<\/p>\n
    switch(item)<\/p>\n
    {<\/p>\n
        case int i:<\/p>\n
            Console.WriteLine($"It's an integer: {i}");<\/p>\n
            break;<\/p>\n
        case string s:<\/p>\n
            Console.WriteLine($"It's a string: {s}");<\/p>\n
            break;<\/p>\n
        \/\/ \u66f4\u591a\u6a21\u5f0f\u5339\u914d\u7684\u60c5\u51b5<\/p>\n
    }<\/p>\n
}<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u6a21\u5f0f\u5339\u914d\u8ba9\u6211\u4eec\u4ee5\u4e00\u79cd\u66f4\u58f0\u660e\u6027\u7684\u65b9\u5f0f\u6765\u68c0\u67e5\u548c\u8f6c\u6362\u7c7b\u578b\uff0c\u66f4\u7b80\u6d01\u5730\u5904\u7406\u591a\u6761\u4ef6\u5206\u652f\u3002<\/p>\n<\/p>\n
\u901a\u8fc7\u4ee5\u4e0a\u65b9\u6cd5\uff0c\u6211\u4eec\u53ef\u4ee5\u5b9e\u73b0\u66f4\u6e05\u6670\u3001\u66f4\u6613\u4e8e\u7ef4\u62a4\u5e76\u4e14\u66f4\u52a0\u7075\u6d3b\u7684\u4ee3\u7801\u3002\u5728\u9009\u62e9\u9002\u5408\u7684\u66ff\u4ee3\u65b9\u6848\u65f6\uff0c\u5173\u952e\u662f\u4e86\u89e3\u6bcf\u79cd\u6280\u672f\u7684\u4f18\u52bf\uff0c\u5e76\u6839\u636e\u5b9e\u9645\u60c5\u51b5\u505a\u51fa\u6700\u5408\u9002\u7684\u9009\u62e9\u3002<\/p>\n<\/p>\n
\u76f8\u5173\u95ee\u7b54FAQs\uff1a<\/strong><\/h2>\n
1. \u5982\u4f55\u5728C#\u4e2d\u4f7f\u7528\u7b56\u7565\u6a21\u5f0f\u6765\u66ff\u4ee3if-else\u548cswitch-case\uff1f<\/strong><\/p>\n
\u7b54\uff1a\u7b56\u7565\u6a21\u5f0f\u662f\u4e00\u79cd\u8bbe\u8ba1\u6a21\u5f0f\uff0c\u53ef\u4ee5\u5e2e\u52a9\u6211\u4eec\u901a\u8fc7\u5b9a\u4e49\u4e00\u7cfb\u5217\u7684\u7b97\u6cd5\u6765\u66ff\u4ee3\u590d\u6742\u7684if-else\u548cswitch-case\u8bed\u53e5\u3002\u5728C#\u4e2d\uff0c\u6211\u4eec\u53ef\u4ee5\u521b\u5efa\u4e00\u4e2a\u63a5\u53e3\u6765\u5b9a\u4e49\u7b97\u6cd5\u7684\u6267\u884c\u65b9\u6cd5\uff0c\u7136\u540e\u9488\u5bf9\u4e0d\u540c\u7684\u60c5\u51b5\u5b9e\u73b0\u4e0d\u540c\u7684\u7b97\u6cd5\u7c7b\u3002\u901a\u8fc7\u4f7f\u7528\u7b56\u7565\u6a21\u5f0f\uff0c\u6211\u4eec\u53ef\u4ee5\u5c06\u7b97\u6cd5\u7684\u9009\u62e9\u4e0e\u5177\u4f53\u7684\u4ee3\u7801\u5206\u79bb\uff0c\u63d0\u9ad8\u4ee3\u7801\u7684\u53ef\u7ef4\u62a4\u6027\u548c\u53ef\u6269\u5c55\u6027\u3002<\/p>\n
2. C#\u4e2d\u662f\u5426\u6709\u5176\u4ed6\u66ff\u4ee3if-else\u548cswitch-case\u7684\u8bed\u6cd5\u7ed3\u6784\uff1f<\/strong><\/p>\n
\u7b54\uff1a\u9664\u4e86if-else\u548cswitch-case\u8bed\u53e5\uff0cC#\u4e2d\u8fd8\u6709\u5176\u4ed6\u53ef\u4ee5\u66ff\u4ee3\u5b83\u4eec\u7684\u8bed\u6cd5\u7ed3\u6784\u3002\u4f8b\u5982\uff0c\u53ef\u4ee5\u4f7f\u7528\u4e09\u5143\u8868\u8fbe\u5f0f\u6765\u5b9e\u73b0\u7b80\u5355\u7684\u6761\u4ef6\u5224\u65ad\uff0c\u5b83\u7684\u8bed\u6cd5\u5f62\u5f0f\u4e3a\uff1a\u6761\u4ef6 ? \u8868\u8fbe\u5f0f1 : \u8868\u8fbe\u5f0f2<\/code>\u3002\u53e6\u5916\uff0cC# 7\u53ca\u4ee5\u4e0a\u7248\u672c\u4e2d\u8fd8\u5f15\u5165\u4e86\u6a21\u5f0f\u5339\u914d\u8bed\u6cd5\uff0c\u53ef\u4ee5\u66f4\u65b9\u4fbf\u5730\u5bf9\u4e0d\u540c\u7684\u6a21\u5f0f\u8fdb\u884c\u5339\u914d\u548c\u5904\u7406\uff0c\u7528\u4e8e\u66ff\u4ee3\u590d\u6742\u7684if-else\u548cswitch-case\u903b\u8f91\u3002<\/p>\n
3. \u5982\u4f55\u4f7f\u7528\u59d4\u6258\u548cLambda\u8868\u8fbe\u5f0f\u6765\u66ff\u4ee3if-else\u548cswitch-case\uff1f<\/strong><\/p>\n
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