无法将类型...隐式转换为...问题

Question

我有这个代码：

       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

我想尝试让 myCustomerList 将值保留在枚举器中并返回它。

Answer 1

问题是您期望返回 DAl.dcCustomer 类型，但 linq 语句返回 ConnectionWeb.Customer 类型...

您可以通过更改来解决此问题:

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

至：

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，而不是像您假设的那样 ConnectionWeb.DAL.dcCustomer 。