使用LINQ to刪除列表中的項目沒有在另一個列表

Question

//basic item class 
public class myItem 
{ 
    public Int Id { get; set;} 
    public String Name { get; set;} 
} 

//My original List 
List<myItem> masterList = new List<myItem>() { new myItem{id = 1, Name = "item 1"}, 
              new myItem{id = 2, Name = "item 2"}, 
              new myItem{id = 3, Name = "item 3"}, 
              new myItem{id = 4, Name = "item 4"} 
              }; 

//List of ids of items I want to KEEP in my original list 
List<int> keepList = new List<int>() {2,3}; 

基本上我想要刪除的arent ID 2或3，從我的主人名單

Answer 1

public class myItem 
{ 
    public int id { get; set;} 
    public String Name { get; set;} 
} 

void Main() 
{ 
    //My original List 
    List<myItem> masterList = new List<myItem>() { new myItem{ id = 1, Name = "item 1"}, 
              new myItem{id = 2, Name = "item 2"}, 
              new myItem{id = 3, Name = "item 3"}, 
              new myItem{id = 4, Name = "item 4"} 
              }; 

    //List of ids of items I want to KEEP in my original list 
    List<int> keepList = new List<int>() {2,3}; 

    // what you want 
    masterList = masterList.Where(i => keepList.Contains(i.id)).ToList(); 
}