如何在具有一对多关系的 ListView 实体中显示

Question

我有一个包含 3 个 DbSet 和一对多关系的上下文类： (1)地点 - 大学(许多) (1)大学 - 评分（多）

而且我需要在 wpf 的列表视图中显示对所有评级的查询结果。 但是 listView 不显示来自大学和位置的字段。

查询示例：

  using (var c = new Context())
        {
            ratingListView.ItemsSource = (from w in c.Ratings
                     where w.Year.Value == 2012
                     select w).ToList();
        }

ListView 绑定：

<GridViewColumn Header="Rank" Width="Auto" DisplayMemberBinding="{Binding WorldRank}"/>
                    <GridViewColumn Header="Institution" Width="120" DisplayMemberBinding="{Binding Unviversity}"/>
                    <GridViewColumn Header="Location" Width="60" DisplayMemberBinding="{Binding Location }"/>
                    <GridViewColumn Header="National&#x0a;   Rank" Width="60" DisplayMemberBinding="{Binding NationalRank }"/>
                    <GridViewColumn Header=" Quality of &#x0a; Education" Width="70" DisplayMemberBinding="{Binding QualityOfEducation}"/>
                    <GridViewColumn Header="  Alumni of &#x0a;Employment" Width="70" DisplayMemberBinding="{Binding AlumniEmployment}"/>
                    <GridViewColumn Header=" Quality of &#x0a;    Faculty" Width="70" DisplayMemberBinding="{Binding QualityOfFaculty}"/>
                    <GridViewColumn Header="Publications" Width="70" DisplayMemberBinding="{Binding Publications }"/>
                    <GridViewColumn Header="Citations" Width="60" DisplayMemberBinding="{Binding Citations }"/>
                    <GridViewColumn Header=" Broad &#x0a;Impact" Width="50" DisplayMemberBinding="{Binding BroadImpact}"/>
                    <GridViewColumn Header="Patents" Width="60" DisplayMemberBinding="{Binding Patents }"/>
                    <GridViewColumn Header="Score" Width="60" DisplayMemberBinding="{Binding Score }"/>

Answer 1

您只从 Ratings 表中选择了字段，那么您希望如何能够显示来自 University 和 Locations 的字段！

选项 1：

使用导航对象绑定 University 和 Location 列，例如 University.UniversityName 和 University.Location.LocationName（我编造了成员名称，因为您没有提供 EF 的整个结构）。

选项 2：

在linq 查询中包含大学和位置。

 using (var c = new Context())
        {
            ratingListView.ItemsSource = (from w in c.Ratings
                                         join u in c.Universities
                                         on w.UniversityID equals u.ID
                                         join loc in c.Locations
                                         on u.LocationID equals loc.ID
                     where w.Year.Value == 2012
                     select new {loc.Location, u.University, w.field1, w.field2}).ToList();
        }