返回自定义对象<列表T& gt;从实体框架并分配给对象数据源 [英] Return Custom Object <List T> from Entity framework and assign to Object Data Source

问题描述

我需要一个问题的指导，我正在使用Entity Framework 4.0，具有DAL和BLL，并绑定到页面上的ObjectDataSource.

I need some guidance with an issue, I am using Entity Framework 4.0, I have a DAL and BLL and am binding to ObjectDataSource on the page.

我必须使用 PIVOT 和动态SQL编写存储过程，才能以所需的方式从多个实体返回数据.现在，我试图弄清楚如何获取实体框架以返回可以绑定到页面上的 ObjectDataSource 的自定义对象，自存储以来，我需要使用自定义对象或动态对象该过程可以返回任意数量的列，因此我不能使用强类型的类或实体，并且还需要将其与 ObjectDataSource 绑定.

I had to write a stored procedure using PIVOT and dynamic SQL to return the data from multiple entities the way I want. Now I am trying to figure out how can I get Entity Framework to return a custom object that I can bind to my ObjectDataSource on the page, I NEED to use a custom object or a dynamic object since the stored procedure can return any number of columns so I can't use a strongly typed class or entity and I need to be also able to bind this with an ObjectDataSource.

有人可以指出执行此操作的好方法以及如何定义我的函数吗?请提供一些代码示例.

Can someone point out a good way to do this and how to define my function? With some code examples please.

我读到我应该尝试使用 List< T> 来返回对象，因为EF不支持返回数据表/数据集，到目前为止，我有以下内容，但我知道这是不正确的

I read that I should try to use List<T> for returning an object since EF does not support returning datatables/datasets, I have the following so far but I know this isn't correct.

我对泛型的使用不多，如果您能指出如何做到这一点，那么我相信这对很多人都会有帮助.请提供该函数的代码示例以及如何将 ObjectDataSource 绑定到返回对象?

I have not worked with generics much, if you could point out how to do this I'm sure this would be helpful for a lot of people. Please provide code examples for the function and how to bind ObjectDataSource to the return object?

非常感谢您的帮助！

感谢您的帮助理查德，根据您对DbDataRecord的使用建议，这就是我现在的功能

C#函数

public List<DbDataRecord> GetData(int product_id)
{
    List<DbDataRecord> availableProducts = new List<DbDataRecord>();

    var groupData = context.ExecuteStoreQuery<DbDataRecord>("exec 
  spGetProducts @ProductID={0}", product_id);

    availableProducts = groupData.ToList<DbDataRecord>();

    return availableProducts;
}

ObjectDataSource 在ASPX页面中

<asp:ObjectDataSource ID="ODSProductAvailability" runat="server"
        TypeName="Project.BLL.ProductBL" 
        SelectMethod="GetData"  >
     <SelectParameters>
        <asp:SessionParameter Name="product_id" SessionField="ProductID" />
     </SelectParameters>
</asp:ObjectDataSource>

现在访问页面时出现此错误:

Right now I'm getting this error when I access the page:

结果类型'System.Data.Common.DbDataRecord'可能不是抽象的，必须包含默认构造函数

这是因为 ExecuteStoreQuery 希望被定义为类或实体吗?我该如何基于存储过程的结果创建一个对象并将其分配给它?

Is this because the ExecuteStoreQuery expects to be defined class or entity? How can I just create an object based on the stored procedure results and assign it that?

推荐答案

类似这样的内容:

using (AdventureWorksEntities context = new AdventureWorksEntities())
{
    string myQuery = @"SELECT p.ProductID, p.Name FROM 
        AdventureWorksEntities.Products as p";

    foreach (DbDataRecord rec in new ObjectQuery<DbDataRecord>(myQuery, context))
    {
        Console.WriteLine("ID {0}; Name {1}", rec[0], rec[1]);
    }
}

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