无法隐式转换类型...到...问题

Question

我有这段代码：

       public static IEnumerable<dcCustomer> searchCustomer(string Companyname)
    {
        TestdbDataContext db = new TestdbDataContext();


        IEnumerable<dcCustomer> myCustomerList = (from Customer res
                                                  in db.Customers
                                                  where res.CompanyName == Companyname
                                                  select res);

        return myCustomerList;



    }

无论我尝试什么，我都会不断收到转换错误。

Error 1 Cannot implicitly convert type 'System.Collections.Generic.IEnumerable<ConnectionWeb.Customer>' to 'System.Collections.Generic.IEnumerable<ConnectionWeb.DAL.dcCustomer>'. An explicit conversion exists (are you missing a cast?) \\srv01\home$\Z****\Visual Studio 2008\Projects\ConnectionWeb\ConnectionWeb\DAL\dcCustomer.cs 63 20 ConnectionWeb

我想尝试使用myCustomerList将值保存在枚举器中并返回它。

Answer 1

问题是您希望返回DAl.dcCustome r类型，但linq语句返回ConnectionWeb.Customer类型...

您可以通过更改：

来克服这个问题

IEnumerable<dcCustomer> myCustomerList = 
(from Customer res
   db.Customers
   where res.CompanyName == Companyname
   select res);

为：

IEnumerable<dcCustomer> myCustomerList = (from Customer res
  in db.Customers
  where res.CompanyName == Companyname
  select new dcCustomer(){
   //set properties here...
  });

HTH

Answer 2

在我看来，db.Customers包含ConnectionWeb.Customer类型的对象，而不是像你假设的ConnectionWeb.DAL.dcCustomer。