實體框架返回空值

Question

我正在嘗試將WCF服務中的列表返回給客戶端。

我正在使用Entity Framework來查詢數據庫

我的實體框架庫中有以下代碼：

public List<Users> getUsersByLastName(string pLastName)
{
    using (var context = new AMTEntitiesContainer())
    {
        var users = context.Users
                           .Where((c) => c.LastName.Contains(pLastName))
                           .ToList();
        return users;
    }
}

這就是我在WCF中捕獲結果並將其返回的方式：

public List<wcfUser> getUsersByLastName(string pLastName)
{
    UserMethods userMethods = new UserMethods();
    List<Users> usersList = userMethods.getUsersByLastName(pLastName);
    List<wcfUser> usersListForClient = new List<wcfUser>();
    wcfUser usersForClient = new wcfUser();
    foreach (Users u in usersList)
    {
        usersForClient = new wcfUser();
        TranslateServerUserToClientUser(u, usersForClient);
        usersListForClient.Add(usersForClient);
    }
    return usersListForClient;
}

問題是，由於某種原因，usersList始終為空。為什么？

我通過將相同的查詢放入LINQPad中來檢查數據庫是否為空

Answer 1

這樣就解決了，顯然數據庫正在返回一些奇怪的東西，但這捕獲了它：

private AMTEntitiesContainer context = new AMTEntitiesContainer();

public IEnumerable<Users> getUsersByLastName(string pLastName)
{
    IQueryable<Users> results;

    results = (from m in context.Users
               where m.LastName.StartsWith(pLastName)
               select m);

    return results;
}