c#基础之lambda表达式

Expression lambdas

=> 运算符右侧有表达式的 lambda 表达式称为表达式 lambda。

(input-parameters) => expression

Func<int, int> square = x => x * x;
Console.WriteLine(square(5));

Action line = () => Console.WriteLine();

Func<double, double> cube = x => x * x * x;

Func<int, int, bool> testForEquality = (x, y) => x == y;

Func<int, string, bool> isTooLong = (int x, string s) => s.Length > x;

Statement lambdas

语句 lambda 类似于表达式 lambda，只是它的语句被括在大括号中：

(input-parameters) => { }

Action<string> greet = name =>
{
    string greeting = $"Hello {name}!";
    Console.WriteLine(greeting);
};
greet("World");

Async lambdas

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
        button1.Click += async (sender, e) =>
        {
            await ExampleMethodAsync();
            textBox1.Text += "\r\nControl returned to Click event handler.\n";
        };
    }

    private async Task ExampleMethodAsync()
    {
        // The following line simulates a task-returning asynchronous process.
        await Task.Delay(1000);
    }
}