Lamd表达式

时间:2023-12-19 23:32:32

1. 普通绑定:

public void button1_Click(object sender, EventArgs e)

{

MessageBox.Show("ok");

}

this.button1.Click += button1_Click;

2. 匿名委托:

this.button1.Click += delegate(object sender, EventArgs e)

{

MessageBox.Show("Click");

};

3. LAMDA表达式:

this.button1.Click += ((sender, e) =>

{

MessageBox.Show("Click");

}

);

编译器会自动推算出表达式中的类型。

4. 过滤条件:

List<User> users = new List<User>();

Func<User, bool> predicate = (

(user) =>

{

return user.UserId > 100;

}

);

List<User> temps = users.Where(predicate).ToList();

等同于:

List<User> temps = users.Where(p => p.UserId > 100).ToList();

List<User> temps = (from p in users where p.UserId > 100 select p).

ToList();

List<User> users = new List<User>();

Func<User, bool> predicate =

(

(user) => user.UserId > 100

);

List<User> temps = users.Where(predicate).ToList();

单挑语句时不需要使用{},同时可以不使用return来返回结果。

5. 排序:

List<User> users = new List<User>();

List<User> temp1 = users.OrderBy(p=>p.UserId).ToList();

Func<User, int> orderby = (user => user.UserId);

List<User> temp2 = users.OrderBy(orderby).ToList();