如何在网格视图内的列表内绑定列表？答案

【问题标题】：How to bind list inside list inside grid view?如何在网格视图内的列表内绑定列表？
【发布时间】：2014-08-17 06:39:41
【问题描述】：

我正在通过实体框架检索数据。在用户表里面有一个角色的导航属性。在角色里面有一个属性角色名称。但是当将其绑定到网格并使用 Eval 调用绑定表达式时，我收到以下错误：

DataBinding: Eval("Role.RoleName") is not a valid indexed expression.

我的代码是：

  Entities.VSTMEntities vstmEntities = new Entities.VSTMEntities();

        var lstUser = (from e in vstmEntities.Users
                       select e).ToList();

        gvUserInformation.DataSource = lstUser;
        gvUserInformation.DataBind();

和aspx：

 <asp:GridView ID="gvUserInformation" runat="server" AutoGenerateColumns="False">
                       <Columns>
                           <asp:BoundField DataField="Username" HeaderText="UserName" />
                           <asp:BoundField DataField="Password" HeaderText="Password" />
                           <asp:BoundField DataField="Email" HeaderText="Email Address" />
                           <asp:BoundField DataField="User_Status" HeaderText="User Status" />
                           <asp:BoundField DataField="Eval(&quot;Role.RoleName&quot;)" HeaderText="User Role" />//This causing error
                       </Columns>
                   </asp:GridView>

【问题讨论】：

GridView bound with with Properties of nested class 的可能重复项

标签： c# asp.net linq gridview linq-to-entities

【解决方案1】：

这就是我会做的：

<asp:gridview id="gvUserInformation" runat="server" autogeneratecolumns="False">
    <Columns>
        <asp:BoundField DataField="Username" HeaderText="UserName" />
        <asp:BoundField DataField="Password" HeaderText="Password" />
        <asp:BoundField DataField="Email" HeaderText="Email Address" />
        <asp:BoundField DataField="User_Status" HeaderText="User Status" />
        <asp:TemplateField>
            <ItemTemplate>
                <asp:GridView ID="grid2" runat="server" AutoGenerateColumns="False" Width="100%">
                    <Columns>
                        <asp:BoundField DataField="RoleName" HeaderText="User Role" />
                    </Columns>
                </asp:GridView>
            </ItemTemplate>
        </asp:TemplateField>
    </Columns>
</asp:gridview>

后面的代码：

protected override void OnInit(EventArgs e)
{
  gvUserInformation.RowDataBound += gvUserInformation_RowDataBound;
}

void gvUserInformation_RowDataBound(object sender, GridViewRowEventArgs e)
{
  var grid2 = (GridView)e.Item.FindControl("grid2");
  grid2.DataSource = Role.Where(w => w.RoleName = (e.Item.DataItem as Roles).RoleName);
  grid2.Bind();
}

【讨论】：