List<T>转换为ObservableCollection<T>

ObservableCollection能通知他变化了也正是因为它实现了INotifyPropertyChanged接口，

在wpf项目中经常会遇到把List<T>转换为ObservableCollection<T>.

总结了一下几种方法:

首先有个 Employee实体类:

 public class Employee
    {
        private string name;

        public string Name
        {
            get { return name; }
            set { name = value; }
        }

        private int age;

        public int Age
        {
            get { return age; }
            set { age = value; }
        }

        private string sex;

        public string Sex
        {
            get { return sex; }
            set { sex = value; }
        }

接着有一个返回值为List<Employee>类型的方法:

 /// <summary>
        /// 填充一个List<Employee>
        /// </summary>
        /// <returns></returns>
        public List<Employee> GetEmployeeList()
        {
            List<Employee> list = new List<Employee> 
            {
                new Employee{Name="张三",Age=19,Sex="男"},
                new Employee{Name="李四",Age=20,Sex="男"},
                new Employee{Name="小红",Age=18,Sex="女"},
            };
            return list;
        }

有一个只读的ObservableCollection<Employee>类型的属性：

private ObservableCollection<Employee> employeeList;

        public ObservableCollection<Employee> EmployeeList
        {
            get 
            {
                if (employeeList == null)
                {
                    employeeList = new ObservableCollection<Employee>();
                }
                return employeeList;
            }
        }

集合类型属性设置为只读的好处这里不展开。

最后是调用GetEmployeeList方法获得一个List<Employee>的list,把这个list赋值给ObservableCollection<Employee>类型的集合属性:

 List<Employee> list = GetEmployeeList();
            if (list != null)
            {
                EmployeeList.Clear();
                //方法一如果ObservableCollection集合是可读可写的(set)
                //EmployeeList = new ObservableCollection<Employee>(list); //错误:无法对属性或索引器“EmployeeList”赋值 -- 它是只读的    
                //方法二:遍历list添加到ObservableCollection集合
                //foreach (Employee item in list)
                //{
                //    EmployeeList.Add(item);
                //}
                //方法三：方法二的简写
                list.ForEach(p => EmployeeList.Add(p)); //遍历list添加到EmployeeList中
            }