使用UNION实现LINQ-TO-XML

Question

我正在尝试联合查询以创建一个XML文件。查询本身作为T-SQL工作，但我作为LINQ-TO-XML的实现失败，并显示“无法转换表达式...”错误。

我问错问题了吗？这种方法是完全错误的吗？我是LINQ的新手。如何从2个查询创建单个XML？

Dim db As New SOMEDataContext

Dim members As New XElement("members", _
    (From c In db.Employees _
    Join cf In db.BowlingTeams On c.ID Equals cf.BowlingTeam_Text _
        Where c.DEPARTMENT = "Housewares" _
            Select New XElement("member", _
                New XElement("id", c.ID), _
                New XElement("title", c.TITLE))) _
    .Union(From e In db.Employees _
        Where e.DEPARTMENT = "Housewares" _
        Where e.POSITION Like "*XYZ*" _
            Select New XElement("member", _
                New XElement("id", e.ID), _
                New XElement("title", e.TITLE))))

Answer 1

下面是我在VB中如何做到这一点：

    Dim members = <members>
                      <%= From c In db.Employees _
                          Join cf In db.BowlingTeams On c.ID Equals cf.BowlingTeam_Text _
                          Where c.DEPARTMENT = "Housewares" _
                          Select <member>
                                     <id><%= c.ID %></id>
                                     <title><%= c.TITLE %></title>
                                 </member> %>
                      <%= From e In db.Employees _
                          Where e.DEPARTMENT = "Housewares" _
                          Where e.POSITION Like "*XYZ*" _
                          Select <member>
                                     <id><%= e.ID %></id>
                                     <title><%= e.TITLE %></title>
                                 </member> %>
                  </members>

这利用了XML文本，避免了对所有New XElement调用的需要。

Answer 2

我认为你只需要做这样的事情。不确定VB语法是否正确。

   Dim query As From c In db.Employees Join cf In db.CourseFaculties On c.ID Equals cf.COURSEFACULTY_Text Where c.DEPARTMENT = "Housewares" Select New XElement("member", _
       New XElement("id", c.ID), New XElement("title", c.TITLE))).Union(From e In db.DATATEL_Employees Where e.DEPARTMENT = "Housewares" Where e.POSITION Like "*XYZ*" _
       Select New XElement("member", New XElement("id", e.ID), New XElement("title", e.TITLE)));

   Dim members As New XElement("members");
   foreach (XElement result in query)
       members.Add(result);