c# lambda表达式学习
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();