左加入列表<t>與Datatable -Linq

Question

我有一個List<t>和DataTable。通過使用Linq，我想檢索DataTable中不存在的產品List<Product>的列表。

的product（List<Product>）名單

Number TechnicalDescription 
1   This is the A item 
2   This is the B item 
3   This is the Z item 

表

Name   Description 
A   This is the A item 
B   This is the B item 
C   This is the C item 
D   This is the D item 

結果：List<Product>

Number TechnicalDescription 
3   This is the Z item 

Here是我所需要的提琴手SQL的例子，但使用LINQ。

我試過這個，但不起作用。

List<Product> productList = THE_LIST; 
DataTable dtProducts = THE_TABLE; 

var myNewList = from e in productList 
       join p in dtProducts.AsEnumerable() 
        on e.TechnicalDescription.ToLower() 
        equals p.Field<string>("Description").ToLower() 
        into productGroup 
       from p in productGroup.DefaultIfEmpty(new { ID = "0", TechnicalDescription = "" }) 
       where p != null 
       select new 
       { 
        ID = e.ID, 
        TechnicalDescription = e.TechnicalDescription 
       }; 

Answer 1

試試這個：

var table = 
    dtProducts.AsEnumerable() 
     .Select(r => p.Field<string>("Description")).ToList(); 
var result = 
    productList 
     .Where(p => !table.Any(t => StringComparer.OrdinalIgnoreCase.Equals(t, p.TechnicalDescription)));